Most male gorillas either have a harem or do not have a mate; in contrast, most men who have more than zero mates have only one. This means that, whe… - Steve Stewart-Williams

By clamping down on male aggression, culture may make the sex difference in aggression smaller than it would otherwise have been.

Sex differences in various psychological traits – in particular, average differences in career-related interests – contribute more to STEM gender gaps than is often assumed. These differences are not due solely to learning, but have a biological component as well... Certainly, the evidence for a biological contribution is not beyond criticism. We suggest, however, that the totality of the evidence renders the Nurture-Only view considerably less plausible than the Nature-Plus-Nurture alternative. The evidence we find most compelling includes the stubbornness of the sex differences over time, even despite efforts to eradicate them; the cross-cultural consistency of the differences; the early appearance of some differences during development; evidence linking the traits in question to prenatal hormonal exposure; and in some cases, comparable differences in evolutionarily relevant nonhuman animals. Each of these findings would be more surprising if the relevant sex differences were due solely to culture than if biology were also involved. And although alternative explanations for any particular finding are always possible, the convergence of these very different lines of evidence adds up to a strong prima facie case for a non-trivial biological contribution.

Several years ago, the Foundation for Biomedical Research ran an ad campaign in support of medical experimentation on nonhuman animals. The ad featured a photograph of a group of animal rights protestors under the caption: ‘Thanks to animal research, they’ll be able to protest 20.8 years longer.’ But imagine a parallel universe in which medical research is conducted on black people, and in which an equivalent foundation employs an equivalent argument: ‘Thanks to research on black people, these white protesters will be able to protest against experimentation on black people 20.8 years longer’! Would this justify experimentation on black people? Obviously not! We would immediately reject the argument as founded on a deeply racist assumption, namely, that the costs inflicted on ‘mere’ black people are justified by the benefits produced for whites. But the original argument is founded on an equivalently speciesist assumption: that the costs inflicted on ‘mere’ animals are justified by the benefits produced for us.