True or False?

Many states in the US are currently working to pass legislation banning trans-athletes from competing in women’s competitions. Many of the arguments are made on the basis of biology, and the ‘fact’ that formerly men’s bodies have an advantage over cis-women’s bodies. Underlying these arguments are assumptions and myths about biology, and perhaps the most pervasive of these is the mystique surrounding testosterone.

It is not clear how ideas about testosterone caught the public’s imagination to the extent that science and folklore have interwoven over the last century to produce so much confusion, misinformation and pseudo-science around one hormone. Early hormone researchers may be partly to blame; at that time scientists were so fixated on sexual anatomy and reproduction, that they brushed over testosterone’s myriad effects in the bodies of both sexes, treating this hormone as very narrow — that it is related to masculinity — and overwhelmingly powerful. Neither of which are true. Since then testosterone has been used to excuse men’s bad behaviour, everything from violence in sport to sexual assault, while simultaneously propping up arguments that men’s superior physicality provides natural justification for their privileged position in society. So we thought it was time to bust a few of these myths, you might be surprised how many you thought were true!

Testosterone is the male sex hormone.

False: It’s also the most abundant biologically active steroid hormone in women’s bodies — crucial for female development and well-being. It helps support ovulation, for instance. And testosterone isn’t just a sex hormone, either. In men and women, receptors for the hormone are found in almost all tissues, and it contributes to liver function, metabolism, bone health and cognitive function.

Yes, men generally have much higher levels of testosterone than women. But greater quantity doesn’t equate to greater function (i.e. whales have bigger brains than humans, but brains aren’t more important to whales than to us, nor do those brains have a bigger function in whales’ bodies than humans’ bodies).

Testosterone drives aggression and sexual violence.

False: Scientific studies have shown that even extremely high doses of the hormone don’t increase hostility, anger or aggression.

Testosterone supercharges your love life.

False: Studies of men’s testosterone and their sexual behaviour have found no relationship between the two. A certain (relatively low) level of testosterone is necessary for optimal sexual functioning, but above that threshold, more testosterone doesn’t make much difference, for men or women.

The more testosterone, the better the athlete.

False: Testosterone’s effect on athleticism is not straightforward, in either men or women. At the most basic level, no study has ever concluded that you can predict the outcome of speed or strength events by knowing competitors’ testosteronelevels. And while testosterone does affect parameters related to athleticism, including muscle size and oxygen uptake, the relationships don’t translate into better sports performance in a clear-cut way. Consider a study of 52 teenage Olympic weightlifters — an elite group, male and female. Among the boys, there was no relationship between testosterone levels and strength, and among girls, the athletes with lower levels of testosterone lifted more weight.

So next time you go to blame testosterone for your toddler son’s temper tantrum, or men’s behaviour at work, think twice: it probably has nothing to do with hormones.