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Do hormones make men think of sex?

Do hormones make men think of sex?


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I remember hearing a saying that goes like "men think of sex every 7 minutes (or seconds?)". I take this saying to mean that men have sex related thoughts more often than women.

I'm interested if these thoughts are related to hormone expression within the male body. particularly, I'm interested in the very few seconds before a sexual thought emerges - one moment a man is thinking about daily stuff, next moment his thinking has sexual content. What is responsible for this shift in thinking?

I've read that oxytocin is responsible for men feeling romantic attachment to a partner, but is there a hormone that initiates sexual thoughts or fantasy? For example, would a burst of testosterone increase the likelihood of a man thinking of sex?


Interestingly it does seem as if this is at least in part the case.

Testosterone levels are tied to sexual impulses, but also risky behavior and aggression. Its responsible for sexual drive in women as well. Low testosterone can cause depression and loss of the ability to make decisions.

You'll note that the work cited is done on criminals, patients and rats. Remember that is not medically or scientifically ethical to change the androgen levels of a functioning human being. Testosterone supplements might increase the chances of prostate cancer.

While its not scientific, there's a fascinating set of interviews about how testosterone affects human thinking at this transcript of American life, Act 2 :

After testosterone, there was no narrative. There was no language whatsoever. It was just, I would see a woman who was attractive or not attractive. She might have an attractive quality, nice ankles or something, and the rest of her would be fairly unappealing to me.

But that was enough to basically just flood my mind with aggressive, pornographic images, just one after another. It was like being in a pornographic movie house in my mind. And I couldn't turn it off. I could not turn it off. Everything I looked at, everything I touched, turned to sex.


Does testosterone make you mean?

C harles Ryan has a clinic in San Francisco at which he regularly relieves men of their testosterone. This “chemical castration”, as it is sometimes known, is not a punishment, but a common treatment for prostate cancer. Testosterone doesn’t cause the disease (currently the third most deadly cancer in the UK), but it fuels it, so oncologists use drugs to reduce the amount produced by the testicles.

Ryan gets to know his patients well over the years, listening to their concerns and observing changes in them as their testosterone levels fall. Because it involves the so-called “male hormone”, the therapy poses existential challenges to many of those he treats. They know that every day, millions of people – from bodybuilders and cheating athletes to menopausal women – enhance their natural levels of testosterone with the aim of boosting their libido, muscle mass, confidence and energy. So what happens when production is suppressed? Might they lose their sex drive? Their strength? Their will to win?

The fears are not always groundless. Side-effects can also include fatigue and weight gain. But Ryan has witnessed positives, too. As professor of medicine and urology at the University of California, he has noticed that the medical students who have passed through his clinic in the 18 years that he has been treating prostate cancer invariably comment: “Dr Ryan, your patients are so nice.” He replies, jokingly: “It’s because they don’t have any testosterone. They can’t be mean.”

Could there be some truth in that glib reply? Ryan knew his patients hadn’t always been so kind. Before being robbed of their testosterone, they might have been personable and adept at small talk, but they weren’t nearly as interested in other people. He could feel a hypothesis coming on: that as men’s testosterone levels lower, their capacity for empathy will rise. In his new book, The Virility Paradox, he argues that “the fact that reducing testosterone in these ageing men may lead to increased empathy, more emotional engagement in relationships and a softening of aggression could be something of a silver lining”.

Ryan started measuring his patients’ “empathy quotients”, using a survey developed for studying autism. It’s too early to release detailed results, he says, but “we do see increases in the empathy scores in many patients on the treatment”.

He also dived into the literature on testosterone, attempting to understand what exactly was happening to them. Try as he might, however, he found little conclusive evidence for many of the claims made about testosterone, such as a link between hormone levels and risk-taking or sexual violence. “There’s so much ambiguity in the science,” he says. Many of the studies had been carried out on disappointingly small numbers of people.

Ryan is one of several researchers who are questioning the accepted wisdom about testosterone. It is often wheeled out as an excuse for patriarchal society, in arguments along the lines of: women, with their lower testosterone levels, have evolved to nurture and multitask in the domestic sphere, while men are hardwired to take risks, compete and furnish as many women as possible with sperm, thus ensuring the future of the species. But, as Ryan points out, “obviously behaviour and cognition are extraordinarily complex and don’t pivot on one molecule”.

The psychologist Cordelia Fine makes a compelling case that it is our culture rather than our hormones that most influences gendered behaviours. As she writes in Testosterone Rex (winner of the Royal Society’s science book prize for 2017) testosterone has been blamed for the financial crash of 2007-08, yet studies show that, although women have lower levels than men, they can have a higher appetite for risk – even when it comes to financial decisions. She uncovered similar stories when it came to the evolutionary need for more sexual partners (more babies get made if women sleep around, too) and competition for status.

Fine’s pluck in challenging the scientific status quo could itself be viewed as classic testosterone-fuelled behaviour. She has cojones, you might say. She asserts that many typically female behaviours, such as deciding to have babies, are riddled with risk, only women’s risks don’t seem to count when it comes to testosterone mythology.

While Ryan comes at the subject from a different angle, both authors highlight how little research there is into testosterone in women. And yet we know it is vital to them (for example, oral contraception reduces testosterone levels, which can lead to low mood and libido). It can also influence sexual orientation, Ryan writes, with studies showing that “self-described lesbians are likely to have [indications of] higher foetal testosterone levels than women who identify as heterosexual”.

The lack of research, meanwhile, hasn’t prevented a fierce debate about testosterone’s role in women’s sports, with high levels seen as conferring an unfair advantage. The athlete Caster Semenya, who won a gold medal in the women’s 800m at the 2016 Olympics, has extremely high natural testosterone levels for a woman. She had to prove her gender, and medically suppress the hormone before competing (although this ruling is currently suspended). Meanwhile, in 2016, the International Olympic Committee ruled that transgender women could compete without having had surgery, on condition that their testosterone levels were no higher than cisgender women’s.

Not that testosterone levels are consistent in anyone. They rise and fall all the time, according to season, health, relationship and parental status, age, time of day (higher in the mornings) and emotional responses. When a man hears a woman cry, his testosterone goes down. When a person cares for their child, the “bonding” or “love” hormone oxytocin rises, while testosterone falls. If a threat to status or territory is perceived, testosterone rises again. It’s the situations, the culture even, that seem to pull the hormone’s strings. Testosterone, in both men and women, also works in a “feed-forward” system: when you win at something, you get a spike in testosterone that as well as making you feel dominant and confident, increases your sensitivity to the hormone – encouraging further swagger and quests to win.


Sex biology redefined: Article suggests that genes don’t indicate binary sexes

Imagine being a forty-six-year-old woman pregnant with her third child, whose amniocentesis follow-up shows that half her cells carry male chromosomes. Or a seventy-year-old father of three who learns during a hernia repair that he has a uterus. A recent news feature in Nature mentioned these cases as it elaborated on the spectrum of sex biology. People can be sexed in a non-straightforward way and not even be aware of it in fact, most probably aren't. As many as 1 person in 100 has some form of "DSD," a difference/disorder of sex development.

The simple scenario many of us learned in school is that two X chromosomes make someone female, and an X and a Y chromosome make someone male. These are simplistic ways of thinking about what is scientifically very complex. Anatomy, hormones, cells, and chromosomes (not to mention personal identity convictions) are actually not usually aligned with one binary classification.

The Nature feature collects research that has changed the way biologists understand sex. New technologies in DNA sequencing and cell biology are revealing that chromosomal sex is a process, not an assignation.

As quoted in the article, Eric Vilain, MD, PhD, director of the Center for Gender-Based Biology at UCLA, explains that sex determination is a contest between two opposing networks of gene activity. Changes in the activity or amounts of molecules in the networks can sway the embryo towards or away from the sex seemingly spelled out by the chromosomes. "It has been, in a sense, a philosophical change in our way of looking at sex that it's a balance."

What's more, studies in mice are showing that the balance of sex manifestation can be shifted even after birth in fact, it is something actively maintained during the mouse's whole life.

According to the Nature feature, true intersex disorders, such as those from divergent genes or the inability of cellular receptors to respond to hormones, yield conflicting chromosomal and anatomical sex. But these are rare, about 1 in 4,500. For the 1/100 figure, they used a more inclusive definition of DSDs. More than 25 genes that affect sex development have now been identified, and they have a wide range of variations that affect people in subtle ways. Many differences aren't even noticed until incidental medical encounters, such as in the opening scenarios (the first was probably caused by twin embryos fusing in the woman's mother's womb the second by a hormonal disorder).

Furthermore, scientists now understand that everyone's body is made up of a patchwork of genetically distinct cells, some of which may have a different sex than the rest. This "mosaicism" can have effects ranging from undetectable to extraordinary, such as "identical" twins of different sexes. An extremely common instance of mosaicism comes from cells passing over the placental barrier during pregnancy. Men often carry female cells from their mothers, and women carry male cells from their sons. Research has shown that these cells remain present for decades, but what effects they have on disease and behavior is an essentially unstudied question.

This is an uneasy way to think about bodies in a social world where sex is still defined in binary terms. Legal frameworks rely on being able to classify someone as male or female, and social status is often determined by the sex on a birth certificate. Parents and doctors of intersex infants face thorny ethical questions about potential surgeries, therapies, and how to raise the child. The implications of better understanding and socially recognizing DSDs are huge.

As our understanding of biology continues to advance, our social, legal, and medical systems will have to evolve as well. Check out the Nature feature for a discussion of these problems, as well as more interesting research into the biology of sex.

An earlier version of this story ran under a different headline.


Hormones: What Makes A Woman Different from A Man

As I described in my last post, hormones are substances secreted by various glands or organs throughout the body that have an effect on other organs or organ systems either in a positive or negative way. Men and women have pretty much the same hormones but the production of the sex steroids estrogen, progesterone, and testosterone and how they interact with various organ systems is what makes the genders so different.

Men make predominantly testosterone from the testes in a relatively constant amount, with small amounts of estrogen and progesterone either manufactured by the testes and adrenal glands or converted in the fat or liver from other precursor hormones.
Women produce mainly estrogens and progesterone from the ovaries in a cyclic pattern with a small amount of testosterone from the ovaries and adrenal glands.

Major increase in production of these hormones is the hallmark of puberty with its growth spurt and all the secondary sexual characteristic changes that occur in both sexes at that time. Testosterone dominance in the male produces pubic and facial hair growth, bone and muscle mass growth. Estrogen dominance along with progesterone and a small testosterone contribution in the female produces not only the growth spurt in women but also breast development and the characteristic female pattern of fat deposition. Internal changes include the growth and development of the uterus and its ability to respond to estrogen and progesterone hormone changes (menstruation). A woman’s physiology and psyche are intimately connected to her monthly production of hormones, which stimulate, regulate, and control many vital bodily functions. Unlike in the male, female sex steroid levels fluctuate in a specific pattern controlled by the interaction of the pituitary gland in the brain and the ovary. It is these fluctuations that make women so different from men in so many different areas of physical and mental well being.

Because of the normal patterns of fluctuation during the menstrual cycle, women often experience physical symptoms which occur much less frequently in men. For example, migraine headaches occur almost 3 times more frequently in women and most often just prior to menses when the normal estrogen levels have dropped dramatically. Mood swings and ‘PMS’ seem to be caused by the same drop in estrogen levels. Weight gain, high blood pressure, depression, mental fog, strokes, autoimmune disease, endometriosis, breast cancer, and infertility are some of the problems either caused or worsened by hormonal fluctuations.


Do hormones make men choose between love or sex?

Everyone has a friend who is a “relationship person”. Happier spending their time with one individual rather than sowing their wild oats, relationship people have had numerous long-term partners, and never seem to be without their companion.

Promiscuous friends are the opposite. Swiping on dating apps to tap the pool of local singles (pro tip: no one is picking their spouse based on their Tinder photos), sex-driven individuals would rather keep it casual.

According to a UBC researcher, those behavioral differences might be due to a variation in hormone levels.

Biologically, searching for sex and looking for love are two different things, says Alec Beall, a postdoctoral researcher in UBC’s department of psychology.

Love—defined as a feeling of social bonding—is regulated by a hormone named oxytocin in both men and women. Released in the body in response to stimuli like looking into the eyes of a baby, examining photos of vulnerable kittens, or cuddling, the chemical plays an important role in creating strong, committed relationships, both towards a partner or a child.

In men, testosterone is responsible for regulating the sex drive. Primarily produced in the testes, the hormone at healthy levels plays a role in arousal. While oxytocin is more of a nurturing chemical, testosterone is involved in motivating individuals to pursue casual sex.

According to Beall, a high sex drive and a desire to nurture are opposing motivations.

“My [past] dissertation research looked at priming people to feel tenderness, and seeing how it affected their short-term mating drive,” says Beall. “I showed UBC undergraduates pictures of puppies and kittens, and had them think about what it would be like to take care of them. Then they took a survey that assessed their desire to sleep around. What I found was that when people were in this parental caring mindset, they were less likely to report a desire to sleep around. When we primed them with pictures and erotic scenarios to make them think about a short-term mating encounter, they reported lower tenderness responses to pictures of infants. All these motivations are driven by complex underlying physiological components, which is what drove me to the oxytocin study.”

Beall’s new research will examine whether the reason for those apparently opposing drives—whether to be sexually promiscuous or monogamous towards a partner—are because of oxytocin levels.

His study will bring 25 men and 25 women into the lab at separate times, and give them a dose of either oxytocin or a placebo via a nasal spray.

“What we’re expecting is that people under oxytocin will exhibit a weakened desire to sleep around, because the oxytocin temporarily boosts their desire to parent and nurture,” says Beall. “We hope to capture this change in motivation using several methods. First, we’ll use eye-tracking to note whether a participant’s gaze is drawn more to attractive, short-term sexual opportunities, or to human infants, and to the bodies of attractive swimsuit models or to their faces. Next, we are using questionnaires to assess whether participants report a reduced attraction to short-term mating prospects. Finally, we are using saliva tests to determine how much testosterone participants produce in reaction to erotic stimuli. We’re expecting that oxytocin will increase parenting motivation, and we’re using a number of psychological, behavioural, and physiological measures to see what happens with the short-term mating drive.”

Beall believes that it’s an important evolutionary advantage to have separate hormones for sex and love. Humans have an innate desire to have children, and it’s necessary to acquire a mate to successfully reproduce. In order for those children to survive and pass on that genetic material, however, they have to grow to the age of sexual maturity—which would be more likely with additional adults to look after them.

“Within evolutionary biology, the mating/parenting trade-off suggests that because we have limited bioenergetic resources, we cannot devote them to both parenting existing offspring, as well as producing a bunch of additional offspring,” he says. “Our bodies make an unconscious decision: we either invest in mating, or we invest in parenting.”

Kate Wilson is the Technology Editor at the Georgia Straight. Follow her on Twitter @KateWilsonSays


Transgender People and “Biological Sex” Myths

note: The day this was published,H.R. 2796 — a U.S. congressional bill that would legally re-define “man” and “woman” based on an individual’s “genetic sex,” as a means to rollback transgender rights — started to garner news & media attention. While this essay was not intended to address that bill specifically, it thoroughly undermines its logical, legal, and scientific standing.

I recently penned an essay entitled Deb u nking “Trans Women Are Not Women” Arguments in the hopes that it would be a useful primer for countering such claims. But sometimes, efforts to undermine or exclude trans women rely on a somewhat different tactic which takes the following form: A case will be made that sex is distinct from gender — the former being purely biological in nature, the latter being entirely social. Upon making this claim, it will then be argued that, while trans women may indeed be women (because “woman” is a gender category), we nevertheless remain “biologically male” (a sex category). This line of reasoning is often accompanied by claims that women are oppressed because of their sex (not gender), and therefore feminism should be exclusively for “biological females” (thereby expunging trans women).

While this is not a new argument, it has garnered increased attention after Laci Green (a popular YouTube personality) recently forwarded it in a series of videos and comments. Since social media is actively reacting to Green’s comments and similar claims made by others, I thought that this would be an opportune time to debunk this “trans women are biological males” argument, as well as misconceptions about “biological sex” more generally.

Before I begin, I should mention that I am writing this piece, not only as a trans woman and feminist, but also as a biologist. Many of the points that I make here were argued more thoroughly in my books Whipping Girl and Excluded.

Sex is multifaceted, variable, and somewhat malleable

The primary assumption driving most “biological sex” myths is that there are two discrete mutually exclusive sexes that are immutable (i.e., once born into a sex, you will always be a member of that sex). While there are a number of sexually dimorphic traits — such as chromosomes, gonads, external genitals, other reproductive organs, ratio of sex hormones, and secondary sex characteristics — many times these traits do not all align (i.e., all male, or all female) within the same person, as is the case for intersex and many transgender people.

Also, for each of these different sexually dimorphic traits, some people’s anatomies will fall “in between” or “outside of” what most people consider to be standard for female or male.

So in other words, the term “sex” is neither simple nor straightforward: It refers to a collection of sexually dimorphic traits that are variable both across traits and within each trait. And this is not merely a “trans perspective” on the matter here is an article from Nature (one of the most respected science journals) arguing that, “The idea of two sexes is simplistic. Biologists now think there is a wider spectrum than that.”

In addition to this natural diversity, sex is not entirely immutable. Sure, we may not be able to change our genetic sex (which for most of us remains “yet to be determined,” as relatively few people ever have their chromosomes examined, and some who do receive unexpected results). But reproductive organs may be removed or reconfigured via surgery. And sex hormones can be administered (as they often are for both transgender and cisgender people), and they may alter our secondary sex characteristics — i.e., sexually dimorphic traits that arise during puberty, such as breast development in females, and facial hair growth in males.

People tend to harbor essentialist beliefs about sex — that is, they presume that each sex category has an underlying “essence” that makes them what they are. This is what leads people to assume that trans women remain “biologically male” despite the fact that many of our sex characteristics are now female. However, there is no “essence” underlying sex it is simply a collection of sexually dimorphic traits. Some people will presume that sex chromosomes must be this “essence,” even though we cannot readily see them, plus there are non-XX or XY variants. Others presume that genitals are this “essence” (probably because they are used to determine our birth-assigned and legal sex), although they can vary too, and may eventually change (e.g., if one undergoes sex reassignment surgery). In day-to-day life, we primarily rely on secondary sex characteristics to determine (or more precisely, presume) what sex a person is — and of course, these traits may change via a simple hormone prescription. Like I said, there is no mystical “essence” underlying sex.

Sex is a collection of traits that, while generally dimorphic, can vary greatly in the population, and some can change over time. While the terms “male” and “female” have some utility, we should not view them as strictly dichotomous or mutually exclusive. Rather, “female” and “male” are best thought of as umbrella terms that describe groupings of people (or animals) who generally share many of the same traits, albeit with considerable variability and some exceptions.

The “mind/body” dualism fallacy

The gender/sex distinction is rooted in mind/body dualism, which was once commonly accepted, but has since been rejected by contemporary biologists, cognitive scientists, philosophers, and psychologists (as well as many feminists!).

For the mind (which, in the case of trans women, would include our gender identities and lived experiences moving through the world as women) to be entirely separate from one’s body, the following two things must both be true: 1) our brains must be completely “un-sexed,” and 2) our social gender should not at all impact or influence our biology.

Point #1 (that our brains are completely “un-sexed”) is false. For starters, every single nerve cell in our brains has sex hormone receptors, which turn genes on or off in response to sex hormones such as testosterone or estrogen. None of us can say precisely what effects these hormones elicit in our brains — there is obviously a lot of gender diversity among human beings, so it is likely a spectrum of outcomes rather than a binary all-or-none response. But the one thing that we can say is that the notion that our brains remain completely untouched by “sex” is untrue.

More controversially, there is some evidence to suggest that our gender identities are influenced by biology. For those interested, here are some references from my book Whipping Girl that discuss this:

This evidence includes the findings that a few microscopic regions of the brain display sexual dimorphism, and that, in these regions, trans women’s brains appear more female-typical than male-typical. Even more persuasive is the fact that a majority of genetically male children who have been (without their knowledge) raised from birth as girls because they did not have a penis (due to botched circumcision, or the non-intersex condition cloacal exstrophy) eventually come to identify as boys and men, despite their gender socialization to the contrary. These examples demonstrate that biological sex can influence gender (thereby disproving point #1).

[a necessary aside: I can imagine the “trans women are biological males” camp responding, “But if there is such a thing as intrinsic ‘brain sex,’ then Julia, your brain must be male!” To which I respond: I by no means claim that this supposed “brain sex” wholly determines our gender, just that it seems to have an influence upon it. Furthermore, if some kind of “brain sex” does exist, then we should expect it to vary quite a bit within each sex and between sexes, just as all of the other sexually dimorphic traits that I mentioned earlier (e.g., chromosomes, reproductive organs, sex hormones, secondary sex characteristics, etc.) do. If this is true, then trans people may be examples of this variation.]

Point #2 (that our social gender should not at all impact or influence our biology) is also untrue. Our brains physically change in response to our experiences. Here is a list of references from my book Excluded detailing this:

Therefore, my seventeen years of experiences identifying as a woman, being perceived and treated as a woman, and experiencing sexism as a woman, have undoubtedly shaped my brain to some degree. So the notion that my gender does not influence my biology (i.e., point #2) is incorrect, thereby disproving the assumption that mind and body (and by correlation, gender and sex) are entirely separable entities.

[a secondary aside: I can imagine the “trans women are biological males” camp responding, “If our experiences physically alter our brains, then Julia, your socialization as a boy must disqualify you from being a woman!” To which I would respond: 1) by reverting back to gender just then, you have contradicted your own argument, and 2) I suggest that you read my previous essay, particularly the sections on socialization and “kitchen sink” arguments.]

The “nature versus nurture” fallacy

Both the body/mind and sex/gender distinctions are related to “nature versus nurture” debates, wherein people will point to some human trait (e.g., intelligence, personality, or in this case, gender) and argue that the outcome is entirely due to biology/genetics or entirely due to environment/socialization.

While some biologists in the past have forwarded strict “nature” arguments, contemporary biologists acknowledge that most (if not all) human traits arise due to complex interactions between numerous biological factors (both shared biology and individual biological differences) and environment (both shared culture and individual experiences) to create a broad spectrum of outcomes. In Excluded (specifically Chapter 13, “Homogenizing Versus Holistic Views of Gender and Sexuality”), I make this same case with regards to sex and gender.

Clarifying the “sex is a social construct” argument

Sometimes people who are trying to debunk “biological sex” myths will point out that sex (like gender) is a social construct. The reason for doing this is to show that the “biological versus social” distinction is far more muddied (as I have detailed in the last two sections) than the “trans women are biological males” camp is willing to admit.

Unfortunately, people who are unaware of, or misinformed about, social constructivism will often mistake the word “constructed” to mean “fake” or “not real,” and thus assume that such claims represent a denial of the existence of sexually dimorphic traits. However, this is not what the word “constructed” means.

Saying that sex is “socially constructed” does not mean that biological sex differences do not exist or do not matter. It simply conveys that our definition of sex, and the way that we categorize people into sexes, is determined by society and our assumptions about how the world works.

In our society, people are assigned a legal sex at birth based on the presence or absence of a penis — that is a social process. When people argue that it must be chromosomes, or a particular reproductive organ, that defines or determines a person’s sex, that is a social decision — one that ignores the multiplicity and variability of sexually dimorphic traits. Indeed, the very fact that, given the same evidence, people will disagree about the nature of sex (strictly binary versus multifaceted and variable immutable versus somewhat malleable) demonstrates that sex is socially constructed!

So in other words, we can say that biological sex differences exist, and also that our understanding of sex is socially constructed — these are not contradictory statements at all.

Women are oppressed because of both sex and gender

While I disagree with claims that “trans women are biological males,” at least I can understand where they come from: Many people harbor binary and essentialist beliefs about sex, so it’s not surprising that they might come to this false conclusion. However, the notion that “women are oppressed because of their sex, not their gender” is downright ludicrous.

While the sex/gender distinction may serve a purpose in more nuanced or theoretical discussions on the subject, in everyday life most people do not make this distinction. That is, most people use the terms “sex” and “gender” synonymously. Whenever a man speaks over me or down to me, he’s not thinking: “Well, this person appears to me to be biologically female, as opposed to merely identifying as a woman, so therefore I will be misogynistic toward her.” Rather, he simply sees a woman/female (same thing in his eyes), and treats me accordingly.

While it is true that some forms of sexism specifically target female biology (e.g., slurs for breasts and vaginas, attempts to regulate women’s reproductive systems), many other expressions of sexism target traits that fall under the realm of gender (e.g., accusations that women are not mentally or constitutionally fit for leadership positions, comments deriding feminine gender expression, etc.).

Additionally, trans women do experience many forms of sexism that target female biology — in my case, I have experienced slurs targeting my female body parts, sexual harassment, attempted date rape, men ogling and objectifying my body, and so on.

Clearly, “women are oppressed because of their sex, not their gender” is not a serious proposition, nor is it a legitimate feminist concern — it’s merely a bold-faced attempt to exclude trans women. Feminism is a movement to end sexism. Trans women face sexism. Ergo, trans women have a stake in feminism.

The myth that trans people are trying to deny or erase “biological sex” differences

The most infuriating assertion regularly made by the “trans women are biologically male” camp is that trans people are somehow “denying” or “erasing” biological sex differences, and that this hurts cisgender women/“biological females.” This is patently untrue. I can assure you that trans people are highly aware of biological sex differences — the fact that many of us physically transition demonstrates that we acknowledge that sexually dimorphic traits exist and may be important to some people!

I would reframe things this way: Transgender people often have a more complicated relationship with our sex-related traits (as they may be discordant with our identified and lived genders), and thus the language that we use to describe or discuss these traits may seem arcane, or nonsensical, or unnecessary to the average cisgender person. And because they are unfamiliar with this language (and/or flat-out antagonistic toward us), some cisgender people will subsequently misinterpret this language and differing perspective as some sort of “denial.”

While writing about this, I couldn’t help but think back to a patient intake form that I once had to fill out upon visiting a new doctor. The form separated out all the male questions (e.g., when was your last prostate exam) from the female questions (e.g., when was your last breast exam). Multiple items from each sex category applied to me, so I filled out answers in both fields. Honestly, it felt really sucky — not because I’m in denial about my body or my sexual traits, but because the form suggested that who I was should not even be possible.

What I’m trying to convey here is that trans people are not in any way “denying” or “erasing” biological sex differences. We are simply objecting to those who invoke real or imagined biological sex differences in their attempts to exclude us.

Sex and gender are complicated phenomena, and language is imperfect. I personally have no problems with people talking broadly about “female anatomy” or “women’s reproductive rights,” so long as they aren’t purposely trying to erase transgender and intersex people in the process. And (in contrast to lies peddled by Laci Green, Elinor Burkett, and other cisgender feminists) I (and virtually all other trans people) have absolutely no qualms with women talking about their vaginas or other body parts, provided that they are not asserting that these sex attributes apply to all women, or denying the fact that some men may possess them as well.

But in my experience, when people go out of their way to use the clunky phrasing “biological male/female,” they are almost always attempting to contend that 1) biology trumps trans people’s gender identities and lived experiences, and 2) dismiss the reality of gender and sexual diversity, and the fact that there are exceptions to every sex and gender category. If this is your intention, then you should know that I am not “denying” or “erasing” sex differences. I am simply pointing out that you are uninformed about these matters and/or an outright bigot.


Male Hormone Cycle

Instead of having a month-long hormone cycle like women, men go through an entire hormone cycle every 24 hours.

Men also have about 10 times more testosterone than women, so their hormone cycle is usually all about how their testosterone affects them. A man’s body does make estrogen and progesterone like a woman’s body, but in much smaller amounts.

Here’s a timeline of what you can generally expect from a man’s daily hormone cycle:

Morning: Testosterone is highest

Once he shakes off the fog of sleep, high testosterone makes him more energetic, talkative, aggressive, focused, competitive, independent, impulsive and confident. During these peak testosterone hours, he may also be more easily angered (for instance, if he stubs his toe, he might lose his top) and be more likely to say “no” to a favor or request. His virility is at a high point. So is his ability to put together furniture, read maps and do other tasks that require spatial skills.

Best time for him to… assemble a DIY desk, compete in a contest, work on a project solo, figure out the best driving route, enjoy passionate sex.

Afternoon: Testosterone is in the middle of its cycle

He’s a tad mellower than his morning self, but isn’t going on empty just yet. As a result, he’s still upbeat, driven and focused, but not as easily ticked off (that stubbed toe would likely elicit a much shorter, less intense burst of swear words). He’s more open to working with others rather than going solo.

Best time for him to… work as part of a team, pitch clients or customers, brainstorm ideas, go on a date.

Evening: Testosterone is lowest

With testosterone bottoming out, he tends to be more passive, agreeable and low-key, making this a good time to ask him for a favor or other request since he’s more likely to grant it. He may feel tired or fuzzy—especially before he’s had a chance to recharge after work or eat dinner. At this point, his libido hits its lowest point. For some men, this low point is still enough to make them capable of enjoying passionate sex other men may feel too tired for intimacy or have difficulty maintaining an erection.

Best time for him to… do activities that rejuvenate his energy if he wants a pick-me-up (such as playing an instrument or exercising), enjoy relaxing activities in keeping with his current low energy level (such as reading or watching a documentary), cuddle with his partner.


Studies Supporting The Biological Approach on Gender Differences

Notable Studies:

  1. Waber (1976)
    Found that late maturing boys were better at verbal ability than boys who were early developers - suggesting that boys who had less male sex hormones were better (and so more likely to be encouraged to hone their) social skills - associated with female behaviour.
  2. Hampson and Kimura (1988)
    Women were tested at different times of the month. At the times when their oestrogen and progesterone (female sex hormones) were highest, they performed best at fine motor skills but worst in their visual-spatial tasks compared to other times when the levels of these hormones were lower.
  3. Van Goozen et al. (1995)
    Found that transsexuals who underwent 3 months of hormone therapy adopted increased intelligence in the areas that the sex hormones were associated with: female hormone takers gained skills in verbal fluency and became worse at visual-spatial skills and less aggressive. Those that took the male hormones showed the opposite.
  4. Galligani et al. (1996)
    Found that athletes who had taken steroids (increasing levels of testosterone) were more aggressive (a male quality) than those that hadn&apost.

Androsterone is a pheromone that makes men sexually appeal to women. Only 10% of the male population secretes an abundant amount of the pheromone, and these men are considered the sexiest or desirable in the population. Some of these men may not even be physically attractive however, the pheromone Androsterone changes the way people perceive their desirability.

Androsterone is produced by the adrenal gland, testes, and ovaries, and is released through a man's skin, hair, and urine. Women also produce and release the pheromone but at a rate four times less than men. This pheromone is also produced by the sex glands and secreted through sebaceous glands in both the male and female sex organs as smegma and has masculinizing effects on men.


1 Human Penile Spines


Penile spines, as you may know, are spines on the penis. Plenty of animals have them, from the humble field mouse to the proud buffy-tufted marmoset. They&rsquore usually used to rake the inner walls of a female&rsquos vagina after sex to induce ovulation or to prevent the female from mating with anyone else. As it turns out, humans have the genetic coding to create penile spines, too&mdashat some point, we had prickly pickles just like everyone else in nature.

So what happened to them? A team of biologists at the Stanford School of Medicine set out to compare the DNA differences between humans and chimpanzees, one of our closest living relatives, and found a very small but very important deviation. While we still have the genes for penile spines, we lost the switch that activates those genes.

You see, DNA is made up of different types of genomes. Protein-coding genes are like factories&mdashthey make proteins that are assigned to different roles. Non-coding DNA strands are like light switches&mdashthey&rsquore responsible for turning a protein-coding gene on or off at a specific time. In humans, the penile spine protein factory is still there, waiting to be flipped on, but the switch disappeared.

Why? The best guess is that mammals that mate with a lot of partners tend to have more prominent spines, while mammals that practice pair bonding have recessed spines&mdashfor example, chimp spines are more like bumps. At some point, it became more advantageous for humans to pair together for longer, and the spine switch was lost along the way. Love is a beautiful thing.