Book Review: ‘Testosterone: The Story of the Hormone that Dominates and Divides Us’ by Carole Hooven (Part 3)

Chapter 8: T and Sexuality

There’s a story about the US President Calvin Coolidge and his wife touring a poultry farm and being shown around separately. The story might be fictional, but it forms the basis for a joke. The gist of it is that the farmer tells Mrs. Coolidge that the rooster can mate frequently and vigorously to which she replies, “Tell that to Mr. Coolidge.” When Calvin Coolidge is told about the rooster, he asks if it mates with the same hen or with different ones. The farmer tells the President that the rooster mates with many different hens, to which Calvin Coolidge responds, “Tell THAT to Mrs. Coolidge.” This story, whether true or not, inspired the naming of a phenomenon called the ‘Coolidge effect’.

The Coolidge effect is when a male whose sexual interest has declined after mating will experience a renewal in interest when it encounters a new female. This has been observed in many different animals. I was aware of the effect before reading this book but I’m surprised that it was not explored in either of Steve Stewart-Williams’ and David Buss’ books. Carole Hooven suggests that the Coolidge effect may have been an adaptation in males to take advantage of a mating opportunity which could be costly if not pursued. The neurotransmitter dopamine, which is involved in motivation, and T are both involved in creating and recreating this sexual interest.

The description of this effect introduces the theme of this chapter: how T influences sexuality and sex drive. A well known difference between men and women, for instance, is that men typically have a higher sex drive and a greater desire for more sexual partners than women. Evidence for this includes men’s greater consumption of prostitutes and pornography. Studies have also shown evidence of the Coolidge effect in men watching pornography as sexual arousal increases when a new woman is introduced. T is partly responsible for this difference between the sexes.

Sexual and romantic interest emerges at puberty with the release of sex hormones in boys and girls. Boys, of course, will experience a sharp increase in T levels unlike girls. As already established in previous chapters, the T rise in boys influences the parts of their brain that have already been exposed to T in the womb and immediately after birth. Girls experience a release of oestrogen and progesterone instead of T but, in either case, the majority of boys and girls will become attracted to the opposite sex following puberty.

Carole Hooven points out that culture has an effect on sexual behaviour as well. Sexual practices and attitudes can differ all around the world depending on a particular society’s customs. For example, oral sex by boys on men in the Sambia of Papua New Guinea and polygamy among Mormons in the United States is/was acceptable despite both activities been condemned in many other cultures. Attitudes towards homosexuality also vary from being accepted (some might say to an excessive degree) in Western countries and rejected (again, perhaps to excess) in regions such as Africa and the Middle East. Regardless of these factors, the difference in men and women’s sex drive is a consistent finding cross-culturally which indicates that biology is involved.

The reason for the difference in sex drive and sexual variety between males and females has already been partly explained in Chapter 6 with the stags on Rum: males who compete and obtain the most females can increase their reproductive success. By contrast, females have no greater reproductive success competing for a harem of males.

However, Chapter 6 also shows that males of different species will vary in their behaviours. Rum stags are not involved in caring for their offspring whereas male birds will pair bond with females to care for their young. This is because deer calves can survive without any paternal investment whilst birds are helpless as chicks. Similarly, human babies are completely helpless when they are born unlike deer who can walk a few hours after birth. Like birds, humans pair bond to care for offspring.

Carole Hooven writes:

“Not surprisingly, women tend to prefer mates who don’t just have high social status but who also signal willingness to invest in them and their children. Men who fail to signal these qualities and who are just out for a good time may have a harder time finding healthy, fertile mates because women are exercising their reproductive choices.”

There is logic to this but pick-up artists (PUAs) may well disagree with what Carole Hooven claims here. Whether or not you approve of what PUAs do, these men have been successful in attracting women without necessarily signalling to such women they are going to invest in her or her children. Furthermore, how many young women are simply “out for a good time” like men? Moreover, there are men who have fathered children with different women despite not sticking around afterwards.

The author notes that men benefit from staying to raise offspring since, like birds, paternal investment increases the likelihood of babies surviving. T levels will vary depend on if men are trying to attract women or in a committed relationship as previously explained in the book. Men in a relationship or caring for offspring will have lower T:

“Lower T in this situation is associated with being a more devoted partner.”

Again, there is logic to this but women may be less attracted to men who have decreased T. Also, low T has disadvantages in men such as low energy and possibly depression which is not good for relationships.

Similar to the “challenge hypothesis” explained in the sixth chapter, men who have children can experience a rise in T in certain situations such as hearing their baby crying which is possibly to trigger a protective response.

In my opinion, the T levels of men who are single or in a relationship are at what the author has previously called the “Goldilocks level” or “just right” rather than being simply high or low. Carole Hooven noted in the beginning of the book that we typically associate T with men even though women also have T so talking about “high T levels” and “low T levels” can come across as saying “more male” or “more female”. In other words, if men have low T in relationships, this could be seen as being “more female” and therefore better than “more male” high T.

This chapter also analyses the role T may play in influencing sexual orientation. The book claims that the only exclusive homosexual behaviour observed outside of humans is in male domesticated sheep although does not state whether this is in the presence or absence of females. However, Chapter 4 showed that hormonal exposure can affect sexual behaviour such as female rats exposed to T in the womb and in adulthood engaging in mounting which is a predominately male trait.

Although human homosexuality is more complicated, Carole Hooven points out that the stereotype of “lesbian mechanics and gay flight attendants” – i.e. homosexual men and women exhibiting behaviour typical of the opposite sex – has some truth to it. Lesbians and gay men are more likely to identify themselves as less feminine or masculine respectively and are more likely to be in professions that are atypical of their sex.

In childhood, girls who identify as lesbian when they grow up are more likely to show typical boy behaviour such as rough and tumble play and playing sport while boys who identify as gay later on can behave in more female-typical ways.

If T plays a part in developing sexual preferences, it appears to have more of an effect on females than males as there is more evidence of increased T creating lesbian-typical traits than low T creating traits typical of gay men. For example, girls with CAH (mentioned in Chapter 4) are exposed to high levels of T in the womb and are more likely to behave like boys and be attracted to women when they grow up. Nevertheless, Carole Hooven concludes that is unclear if T influences sexual orientation as it is difficult to measure the amount of T that babies may be exposed to in the womb and we do not know exactly when fetal brains differentiate to become male or female.

Although some gay men may identify as less masculine than heterosexual men, gay men are more likely than lesbians to engage in casual sex with many partners, tieing in with the earlier point of men preferring sexual variety more than women.

The author writes:

“In comparison with their straight cousins, on average, gay men do have many more sexual partners. Lesbians do not, and are much more likely to be sexual within committed monogamous relationships.”

Like Steve Stewart-Williams, who makes a similar point in his own book, Carole Hooven does not mention that married lesbian couples are more likely to divorce than other couples so shouldn’t necessarily be seen as the gold standard for committed relationships. The point about sexual variety still stands though:

“Gay men have more sex simply because they can, it’s not a “gay” thing, it’s a “man” thing.”

Here are some other interesting points from Chapter 8:

  • It is unclear if T increases sex drive in women like in men since T is harder to measure in women. T and oestrogen also both peak around ovulation and vary during the menstrual cycle. Other factors such as age and cultural norms can also play a role. Women with conditions like CAIS (which means they are unresponsive to androgens like T) can show typical sexual responses.
  • “Digit ratio” of fingers may indicate the level of early T exposure in the womb. Men and women differ on average in the length of their index finger (the second digit or ‘2D’) relative to their ring finger (fourth digit or ‘4D’) which gives the digit ratio (2D:4D). Men and women’s index and ring fingers are either roughly the same length (which is the case for me, not that anyone cares) or one finger is slightly longer than the other one. In women, the index finger is more likely to be longer than the ring finger and vice versa for men. This means that women’s digit ratio will be higher than men’s. This relationship has been observed in utero and in other vertebrates. This is only a “noisy” signal of T – i.e. has some correlation but is weak – but could be useful to measure group differences. The image below might make this clearer.

Chapter 9: T and Transgenderism

In the book’s penultimate chapter, Carole Hooven explores men and women who have gender dysphoria or are “transgender” and how T may be involved in this. She interviewed several people who either “transitioned” female-to-male (FtM) or male-to-female (MtF) in addition to people who transitioned back.

The author notes:

“Trans people who drastically alter their T levels are in a unique position to offer insights into how life is different when they cross over the other side of the testosterone line.”

The number of people who identify as transgender has risen greatly over the past few years, partly in my view because of its ubiquity in political discourse. According to the book, in one review, the number of people in the US who identified as “trans” in 2017 was double what it was a decade earlier. Additionally, in the UK, referrals to the NHS Gender Identity Development have risen 50-fold.

The author mentions a couple of famous transgender cases such as Jazz Jennings, a MtF celebrity who was apparently diagnosed with gender dysphoria at age 3 and Buck Angel, a FtM celebrity who looks like, in Dr. Hooven’s words, a “heavily tattooed version of the action hero Vin Diesel.”

Given the dramatic effects “transitioning” from one sex to resemble the other can have, there are unique complications for both FtM and MtF cases.

As described in Chapter 5, the effects of T on the body of men, or DSD individuals like Caster Semenya, are difficult to suppress even with hormone therapy. The physical changes undergone during male puberty cannot be undone by increasing hormones like oestrogen.

Carole Hooven compares the difficulties of MtF transitioning to renovating a property. The parts of a property that require maintenance such as the decorating or gardening can be easily modified but the more stable parts such as the brick walls cannot be easily changed.

In the case of a male body transitioning to resemble a female body, the “brick wall” components such as bones, facial structure and vocal cords will remain the same in the absence of T and are difficult to change. Conversely, the “maintenance” components of the body like muscles, fat and reproductive system are less difficult to modify as they rely more on T.

As the author explains:

“Testosterone’s bricklike effects are the reason that physically transitioning in the male-to-female (MtF) direction is so much harder than the reverse (FtM).”

Dr. Hooven interviewed a MtF individual named “Kallisti” who began transitioning to a woman in his(her?) early 30s and the author points out the obvious difficulties:

“I had to make an effort to override the masculine signal her voice sent over the phone, and it was easy to see why this could make life difficult for Kallisti.”

Hormones act on the larynx or “voice box” which affects, amongst other things, the pitch and quality of voice. During male puberty, T binds to androgen receptors in the tissues of the voice box to strengthen and elongate them which increases the depth of voice. Only surgery on the vocal cords can alter this as hormones will have no effect. It is easier for a FtM individual to change their voice to be more masculine but this still might not be as deep as a normal male due to the different size and shape of a woman’s voice box.

“Laryngeal prominence” otherwise known as ‘Adam’s apples’ are more prominent in men than in women to the point where it is sometimes believed that women do not have one. Adam’s apples protect the vocal folds and are joined together by cartilage tissue at a sharper angle in men which is what causes the greater protrusion. During FtM transition, increasing T will lead to a slight growth in Adam’s apples.

High T also means more “terminal” body hair which is coarser and darker than soft, pale “vellus” hair. DHT, mentioned in previous chapters, is responsible for stimulating this hair growth. For FtM transitioning, hormone exposure will result in an increase in hair on the body and face. For MtF cases, it is more difficult to reverse the effects of androgens on creating body hair since terminal hair cannot be reversed back into vellus hair. Often procedures such as laser treatment are needed.

The changes that occur in male and female bodies during puberty makes it difficult for those with gender dysphoria to have the body that they believe correlates with the sex they identify with. “Puberty blockers” are used to prevent the natural development of boys and girls into men and women as a way for people who struggle with their sex identity to “buy time” and decided whether they want to transition or not.

As you can imagine, puberty blocker use has increased and is very controversial. Puberty blockers were originally created to treat children who suffered from “precocious puberty”, in other words, puberty that starts in children much earlier than it is supposed to. This fact reminded me of plastic surgery, which was originally intended to treat people who had been mutilated and disfigured but was then used for more controversial purposes such as cosmetics.

Carole Hooven interviewed a child called “Sasha” who is a boy who took puberty blockers and is a potential MtF case. Although Sasha preferred girls clothes and items over boy’s, he was reluctant to use feminine pronouns and identifies as “non-binary”.

From what Sasha tells Dr. Hooven during their interview, I get the impression that there may have been some outside pressure involved as well, as Sasha has been to “transgender sleep-away camp” for a few years and then went to a “gender clinic” after friends from the camp went to one. Here’s what Sasha said when asked about being offered puberty blockers:

“I was more leaning towards it, but not that much. So when they asked me, do you want a puberty blocker? I said, oh, maybe, maybe not. Not really sure…I had…five other meetings and…I was, like, “probably”, “most likely”, “yeah”, “I really want to…”


Sasha does not want to go through male puberty but also does not want to completely identify as female. After taking a puberty blocker, Sasha claims that he may start taking oestrogen even though he is unsure he wants to. He would not mind having female traits, but does not want to have “male everything”.

Carole Hooven takes an impartial position, which is fair enough, but I think that Sasha may need counselling of some kind to ascertain why he feels the way he does rather than simply being placed on puberty blockers.

Puberty blockers tend to work “upstream” by blocking signals from the brain telling the body to produce sex hormones rather than directly blocking sex hormone receptors “downstream”. The most widely used puberty blocker actually activates the gonadotropin-releasing hormone (GnRH) receptor which is vital to trigger puberty.

This seems paradoxical, but the blocker triggers a constant response from the GnRH receptor rather than the normal response of gradual “hits” which are necessary to trigger a response from the pituitary. Constant activation rather than intervals of activation result in the pituitary no longer responding to signals from GnRH. Therefore, there is no sex hormone release.

The author explains that there is very little research on the long-term effects of blocking puberty in children with gender dysphoria as the practice is relatively new. There are some predictable outcomes however: children who have been given puberty blockers tend to be shorter and lack the physical development of other children going through puberty. Additionally, since puberty increases bone strength, blocking puberty could lead to permanently weak bones.

Although puberty will resume when children on puberty blockers stop using them, such children/adolescents will be “out of sync” with their peers which can cause emotional and psychological difficulties. Similarly, starting puberty later may not result in the same outcomes as normal puberty. Carole Hooven also notes that blocking puberty may reduce opportunities for gender-dysphoric children to explore their feelings about identity which is common for all adolescents.

According to the book, 95% of children who take puberty blockers will decide they want to transition and take cross-sex hormones. As already described, the effects of cross-sex hormones are less reversible than puberty blockers.

Dr. Hooven writes:

“When someone decides to hormonally transition, no matter their age, they are signing up for a lifetime of medical dependence on hormones.”

Fertility will also be affected depending on when gender-dysphoric children stop taking puberty blockers or start taking cross-sex hormones. Puberty may proceed long enough for sperm or eggs to be produced which could be harvested before transitioning.

Given the complexity and controversy around all of this, the author wisely argues:

“Particularly where blockers are concerned, parents and caregivers should consult with qualified professionals, preferably getting a second or third opinion…to provide the best support possible to young people who are making these life-changing decisions, much more research is required.”

This chapter concludes by exploring people who transitioned from one sex to the other before deciding to “detransition” and re-identify with their biological sex. Having been exposed to cross-sex hormones, both FtM and MfF individuals have experience about what it is like to occupy a male and female-typical body. Here are some of the changes that occur which reflect sex differences:

  • FtM and MtFs experience a change in libido. For example, “Alan”, who was FtM, noticed an increase in libido whereas Kallisti (mentioned before), a MtF, experienced a decreased libido but orgasms became a “whole body experience”. “Stella”, a FtM who detransitioned back into identifying as female, noticed an increase in libido which then decreased after stopping cross-sex hormones.
  • FtM cases like Alan and Stella noticed they cried less when taking cross-sex hormones like T. Their “emotional threshold” was higher. The author notes that women cry more and are more likely to have depression. I would point out here though that men’s suicide rate is three times higher than women’s.
  • Kallisti (MfF) became less physically angry after transitioning. However, Carole Hooven argues that changes in anger with or without T are no consistent:

“there’s no reason to think that T will turn a placid female-to-male transitioner into a hot-tempered Incredible Hulk.”

Although T obviously has an effect on the brains and body of those who transition female-to-male, as well as its absence in male-to-female individuals, it is not known if variations in T levels in the womb have any effect on whether a boy or girl will have gender dysphoria.

Nonetheless, there is some evidence that girls who had high prenatal T levels are more likely to have gender dysphoria, similar to the greater likelihood of high-prenatal T girls beings lesbians when they grow up.

Chapter 10: T and Conclusion

The final chapter of the book is also the weakest as it is essentially a summary of the content covered previously. Carole Hooven also weighs in on more social and political issues relating to T which, as I’ve already mentioned, is where the book is less convincing.

Dr. Hooven describes how both men and women are often frustrated by each other’s behaviour but, since men are the primary focus of the book, the attention here is on women’s feelings about men, or, as they may exclaim, “Men!”:

“My personal impression is that these somewhat playful “Men” sighs are a reaction to an objectifying sexuality, difficulties listening and expressing emotions, or ego insecurities that seem to motivate an unearned sense of confidence about, well, almost everything.”

The author does admit that this remark “has the ring of sexism” which is why women often only utter it around other women. The last point about men having “an unearned sense of confidence” is indicative of the idea that men and boys need to be ‘taken down a peg or two’ whereas women and girls alternatively need constant encouragement and support. Later, Carole Hooven also mentions men feeling “the need to confidently explain the obvious” which presumably refers to the idea of ‘mansplaining’.

I don’t want to come across as being too upset or ‘triggered’ by these remarks since there’s probably an element of tongue-in-cheek from the author here but a lot of this chapter does come across as Carole Hooven conveying the mentality of “how to solve a problem like men?”

Moreover, she suggests that understanding biology could be useful in helping to deal with societal problems like sexual assault, reflecting David Buss’ point in his book Bad Men:

“Solving problems requires understanding their causes. If we consistently downplay one set of potential causes (say, biological) in favor of another (say, social), then we have failed to do our best to get to the truth. And that means that we have also ignored opportunities to increase women’s safety and equality between the sexes.”

This does sound like using biology and science to push feminist ideas, again similar to Bad Men, but Carole Hooven is right to recognise the importance of biology. She returns to the scepticism of the media towards the effects of T described in Chapter 1:

“The popular press is full of attempts to bring King T down, to show that he is too big for his boots, or more generally to dismiss biological accounts of psychological and behavioral differences the sexes.”

The author describes what she believes are the reasons for this resistance in accepting T’s effects:

“It appears to have its source in three main worries. First, people think that the T view suggests that testosterone is destiny. Second, they think it suggests that male behavior is natural, and thus good or acceptable. And third, they think it suggests men aren’t to blame – their T gets them off the hook.”

Off the hook for what? – you might ask. Sexual assault is one example possibly. The case of Chanel Miller, who was involved in a sexual assault case against Brock Turner, is described here. This case was also mentioned in Bad Men. Miller and Turner were students at Stanford University and Turner was found lying on Chanel Miller on campus around 01:00am by two Swedish students. Turner subsequently tried to run away but was apprehended by the students. Turner was sentenced to 6 months in jail which was considered a miscarriage of justice.

In 2019 Ms Miller, who was known during the case as “Emily Doe”, revealed her identity by publishing the memoir Know My Name. Carole Hooven is sympathetic towards Chanel Miller but the incident between Ms. Miller and Brock Turner appear to be more complicated. I recommend the reader look at these blog posts exploring the case, which was critical of the simplistic narrative put forward by the media. Bob Somerby, who wrote the posts, notes:

“At trial, Turner testified that he and Miller left the frat party together, and that Miller consented to engage in sexual behavior once they got outside. Did Miller voice some such consent? We have no way of knowing, but then again, neither does Miller! By her own account, she doesn’t remember anything she said and did after roughly midnight that night, and the assault occurred a roughly 1 AM.”

The Daily Howler – The Age of the Novel

This post also makes a compelling point:

“In these cases, we’ve moved beyond the already difficult “he said/she said” dynamic to a different state of affairs, in which “he says/she can’t remember.”

The Daily Howler

In short, Miller’s version of events is open to scrutiny given that she was too drunk to remember what was happening which is likely why Brock Turner initially got a light sentence.

Similarly, Dr. Hooven is sympathetic towards the #MeToo movement:

“Testosterone tends to promote high libido and the acquisition of mates, and if a man’s power, a culture’s failures, or a victim’s powerlessness can do the trick, that will be the road taken by some. But we can also put roadblocks in the way. #MeToo is a movement that has made real progress, and hopefully that will continue.”

I’m less enthusiastic about the movement since it is basically the usual ‘female victims, male perpetrators’ narrative but I won’t hold that against the author since support for #MeToo is the mainstream opinion. Also, Carole Hooven does point out in the notes at the end of the book that there may have been some overreach with #MeToo.

The chapter continues with describing the reluctance that some have in accepting the effects of T due to its contribution to “undesirable male behavior” and possibly leading to the conclusion that “there’s nothing that can be done to curb men’s excesses.”

The author argues that being upset about facts does not change them, reflecting that she was upset upon learning her father had cancer but she could not change the fact that he did. This is a good point, but the argument still comes across as ‘men are a problem, and here’s the science to prove it.’

Here’s some similar quotes from the book:

“Some may worry that if people believe that T is responsible for reprehensible male behavior, then it provides men with a free get-out-of-jail card.”

Sort of like women and feminism perhaps? Dr. Hooven also asks:

“What’s the appropriate response to the fact that men do the majority of raping and assaulting, not to mention hoarding the world’s power?”

The idea of men “hoarding the world’s power” is similarly indicative of feminist thinking. Nevertheless, Dr. Hooven balances all of this slightly by acknowledging that men are more likely than women to perform heroic acts as well.

Some of Carole Hooven’s viewpoints were likely influenced by what she reveals in this final chapter: she was once a victim of rape.

She does not elaborate on the details of the incident (not that she has to) but explains that some of her distress at hearing Randy Thornhill’s theory of rape as an adaptation was influenced by her own experience years before. This also influenced her desire to study testosterone:

“It’s only through writing about men and testosterone that I have come to appreciate that my driving desire to learn about testosterone and how it works might have something to do with my own difficult experiences with men. But it hasn’t been all bad: while some men have wounded me, far more have supported, mentored, and encouraged me.”

Overall, I think Carole Hooven is a ‘good egg’ and has intelligence which she’s put to good use. I can also understand why she would be influenced by feminist ideas even though I don’t agree with them.

Summary: I definitely learnt a lot about testosterone from reading this book so I can recommend it for that reason. Carole Hooven does a good job of presenting a lot of scientific information in a clear and interesting way with the help of Felix Byrne’s hand-drawn illustrations. Reading this book alongside The Ape That Understood the Universe should give you a good understanding of sex differences and biology, whether or not you completely agree with the authors.

Thank you for taking the time to read this review.