CoteDAzur. Theories which ascribe aggression to testosterone, like theories which ascribe depression to serotonin levels while ignoring all the environmental factors that cause people's levels of serotonin levels to fall, are generally rubbish. Or hugely simplistic. Studies tend to show that testosterone levels interact in a highly complex way with an array of other neurochemical and hormonal agents in response to an environment, or show that there is not any simplistic link between testosterone or aggression at all. As an article on one study states:
For example: regardless of their gender, the most violent prisoners have higher levels of testosterone than their less violent peers. Yet scientists hypothesize that this violence is just one manifestation of the much more biologically and reproductively salient goal of dominance.
It then asks the very important question:
Which is to say, are high-testosterone males more likely to become violent criminals, or does being a violent criminal raise a man's level of testosterone?
No one really knows the answer, but a growing body of evidence suggests that testosterone is as much the result of violence as its cause. Indeed, both winning a sporting match and beating an opponent at chess can boost testosterone levels. (On the other hand, losing a sporting match, growing old and becoming obese all reduce levels of testosterone.)
So in other words, the way our nervous systems work is as much a RESULT of environmental factors as an innate predictor of behaviour or a determinant of behavioural propensity.
Really, you're suggesting a world in which males are all walking round trying to keep their testosterone fuelled desire to rape, pillage and under in check. If there was the case, then there would not be any naturally meek, mild and gentle men (of which there are lots) and hyper-agressive women (of which there also plenty).
Analogising the behavioural predispositions of human beings to growing hair is silly.
People did try to explain the dominance of blacks by whites in terms of brain differences. And they were racist.
This really is a novel experience. I've never found myself arguing against neuro-essentialist theories of male dominance with a feminist before. It's supposed to be the other way round.