Perhaps our greatest distinction as a species is our capacity, unique among animals, to make counter-evolutionary choices. - Jared Diamond

In particular, while natural selection favors both males and females that leave many offspring, the best strategy for doing so may be different for fathers and mothers. That generates a built-in conflict between the parents, a conclusion that all too many humans don’t need scientists to reveal to them. We make jokes about the battle of the sexes, but the battle is neither a joke nor an aberrant accident of how individual fathers or mothers behave on particular occasions. It is indeed perfectly true that behavior that is in a male’s genetic interests may not necessarily be in the interests of his female co-parent, and vice versa. That cruel fact is one of the fundamental causes of human misery.

How can we explain simultaneously this general pattern of female parental care and also its numerous exceptions?
The answer comes from the realization that genes for behavior, as well as for malaria resistance and teeth, are subject to natural selection.

My hope in writing this book has been that enough people will choose to profit from that opportunity to make a difference.