There are two very fundamental biological differences between men and women:
- Women’s ability to reproduce is limited to a maximum of about one child per year. Men’s ability to reproduce is limited only by the amount of women they can fertilize.
- Women’s minimum investment per child is nine month. Men’s minimum investment is the fertilization.
Neither one of these has changed in the last five million years. Nearly all differences between the behavior and physiology of men and women stem from these two. Here are two revealing examples:
Men prefer to have more sex partners than women do. This is because their reproductive potential stands more to gain from multiple sex partners than women’s does. For women this creates an oversupply of available men willing to have sex with them. This leads to sexual negotiation power.
Women are more family-oriented. Because their reproductive potential has more to lose by not continuing to take care of the baby after birth, evolution has favored women with strong motherly instincts.