I think knowledge is a blessing, not a curse. This is especially true in the case of genetic knowledge. - Matt Ridley

It underscores yet again the fact that what we call personality is to a considerable degree a question of brain chemistry.

"There is no nature that exists devoid of nurture; there is no nurture that develops without nature. To say otherwise is like saying that the area of a field is determined by its length but not its width. Every behavior is the product of an instinct trained by experience.

The study of human beings remained resolutely unreformed by these ideas until a few years ago. Even now, most anthropologists and social scientists are firmly committed to the view that evolution has nothing to tell them. Human bodies are products of "culture," and human culture does not reflect human nature, but the reverse. This restricts social scientists to investigation only differences between cultures and between individuals — and to exaggerating them. Yet what is most interesting to me about human beings is the things that are the same, not what is different — things like grammatical language, hierarchy, romantic love, sexual jealousy, long-term bongs between the genders ("marriage", in a sense). These are trainable instincts peculiar to out species and are just as surely the products of evolution as eyes and thumbs."

Everything can be inherited except sterility. None of your direct ancestors died childless. Consequently, if we are to understand how human nature evolved, the very core of our inquiry must be reproduction, for reproductive success is the examination that all human genes must pass if they are not to be squeezed out by natural selection. Hence I am going to argue that there are very few features of the human psyche and nature that can be understand without reference to reproduction. I begin with sexuality itself.