Some social scientists say that gender is a social construct and that society tends to agree on the roles of its members. Some natural scientists working within the Darwin-Wallace paradigm would say that sex is linked to gender and the biological construct (a product of natural selection) tends to form the basis of the social construct. Thus to some evolutionary biologists, there are only two apparent sexes, male and female.
To some extent this is true, most animals and plants are recognizably male and female. Some plants would have the two sexes in one organism, but still the male reproductive organ is distinct from that of the female one. One of the biggest questions of biology is why there is a need for a male and female. What advantages does sex confer? And what is the tradeoff? Should males and females be in competition? Is gender necessary for sex?
There is one school of thought that say males and females in order to be evolutionary stable should not be in competition with each other. A man like me produces so many sperm cells and a woman would produce not so many eggs. This is the tradeoff. My production of many sperms in my testicles has a physiological cost that may shorten my life. Similarly, a woman needs to invest a lot of energy in gestation that may also shorten her life. The Neo-Darwinian logic would say that a male needs to increase his chances of getting his sperm fertilize a rather rare female egg. Any intermediate strategy is less effective. The statistical tests are not simple but it is there. What has gender got to with this?
Is gender an epiphenomenon of sex? When natural selection ratcheted up, it is likely that gender evolved. The first animals or plants became male and female and started to express apparent differences. This differences are still observed today. Males have their own secondary sexual characteristics and behaviours and females theirs.
And here comes sexual selection. With males trying to have sex with females, they compete and females may compete and select too. And because the strategies to ensure sex are vastly different between males and females, we can be sure that there will be conflict between males and females.
And what does this conflict result in? The animal kingdom is full of strategies that suggest sexual violence. Rape is one of the strategies pursued by males that couldn't compete for mates. That biologists describe this doesn't mean that humans should pursue the same strategy. In an earlier essay I have argued that in evolution these acts have no teleology, even more, no morality. There is nothing in science to support the idea that what is natural is good.
The challenge for humans is to have an appreciation of the animal nature of their sexuality and relate this to what they have constructed around it. Darwin's statement in the "Descent of Man" is likely true. We really still have the marks of our lowly origins. I disagree with some social scientists. We cannot just set aside our evolutionary heritage when dealing with gender and power relations in society. Why are male humans rule their societies? Is this really purely a social construct or a end result of sexual selection by females? There are some convincing statistical evidence that women are attracted to men with power, wealth and status. This is something that the ever so observant of nature Darwin noted and wrote in his "Descent". But humans can easily thumb their nose up this evolutionary psychology logic. I would do so. But should it be at the cost of desexualising what biological evolution has wrought in the name of gender equality? Should men and women be in competition or their genders and sexes complement? Darwin himself could not have imagined the end result of his daring conclusions on the evolution of sex and gender.