behavior is leading to family and social instability on an unparalleled scale. In Western societies, about half of marriages end in divorce. A large percentage of children are born out of wedlock. One in five pregnancies is aborted. Teenage homelessness is largely caused by conflict with stepfathers. Violence between partners is five times as common in cases where the couple cohabits rather than marries. Child abuse is thirty times more common in situations where single mothers have a series of boyfriends.