Many interesting thoughts and insights in this article. A few quotes: For women, pregnancy is a difficult, costly process, and raising children even more so, meaning that sex must be taken seriously. By and large, biology conditions women to avoid casual sex and to connect sex with love. It also pushes them to look for good providers who tend to be older and wealthier. Men, on the other hand, have lots of love to give at no cost to themselves, and they behave in ways that will spread their genes as widely as possible. On this theory, men will settle down with a woman who is fertile and whose fidelity is assured, in order to have legitimate offspring. But they will also sleep around as much as they can, especially with women who possess the key ‘fertility cues’ of youth and physical beauty.