"I think aggression and competitiveness are/seem to be more prominent in males because of testosterone though......"
Okay, still only partway through Cordelia Fine 'Testosterone Rex',.....
This summary article from elsewhere says:
"Taken together, the evidence suggests that the relatively modest doses of testosterone required for clinical purposes are not associated with changes in aggressive or angry behaviour. Moreover, reports of AAS abusers exhibiting high levels of aggressiveness and experiencing episodes of mania or hypomania after taking huge doses of AAS should not be compared with or extrapolated to the effects of therapeutic doses of testosterone."
and:
"In a comprehensive, double-blind, placebo-controlled, cross-over study (O’Connor et al., 2004), increasing testosterone levels in healthy young men did not significantly increase either the interactional (i.e. the frequency of sexual intercourse) or non-interactional (i.e. libido) components of sexual behaviour."
From this page: thepsychologist.bps.org.uk/volume-22/edition-1/testosterone-and-male-behaviours
This page is also interesting, in terms of sex differences:
www.apa.org/research/action/difference.aspx
"For example, after participants in one experiment were told that they would not be identified as male or female, nor did they wear any identification, none conformed to stereotypes about their sex when given the chance to be aggressive. In fact, they did the opposite of what would be expected - women were more aggressive and men were more passive."
Women/girls are definitely taught not to be aggressive, and boys/men are definitely taught that to not be aggressive is a bad thing. We all remember what happened to boys who were seen to be sissies at school................
We know what testosterone does physically, in terms of what happens during development and what happens to genitalia and muscle mass etc, then I think it was assumed that other male behaviours that are supposed to be what males just do, were also linked to this simple clear chemical difference. So, if you've got testosterone, you're like this rather than like that, and the more testosterone, the more you are.............
Except it seems that it isn't actually that simple! And that it seems that oestrogen plays a similar role in the competitive interactions of women as testosterone plays for men. And women have testosterone too.....................