Invited couples into lab videotaped them and measured stress reactions. Found that men are more stressed by arguments women are more argumentative Women dominate in 2 out of 3 arguments. Women are more willing to initiate conflict, more willing to escalate conflict, better able to handle it when it occurs, and quicker to recover from it. Men, in contrast, seek to avoid conflict, try to contain it when it occurs, are less competent in handling conflict, and take longer to recover from it. In any culture studied, concludes anthropologist Donald Symons.
Men are more eager for casual sex while women are more cautions and want relationships.
Among animal species, males are more sexually opportunistic than the females. Tomcats approach the females, fight for access. We have every reason to believe it is in our genes. It is explained by our unequal contributions to reproduction. A woman invests more in a child than a man.