Studies show that the absence of the father expresses itself in male children in two very different ways: it is linked to increased aggressiveness on one hand, and greater manifestations of effeminacy on the other. A 1987 study of violent rapists found that 60 percent of them came from single-parent homes. A Michigan State University study of adolescents who committed homicides found that 75 percent of them were from broken homes. Girls without fathers fare no better. They become sexually active sooner and are more likely to have out-of-wedlock children.