Despite the decline of instinct as a general explanation for behavior,the concept of maternal instinct did not fade from psychological explanations of behavior. Fields as different as primate biology and social policy have shown the influence of assuming that biology determines motherhood and fatherhood(Silverstein, 1993)Scientists and social policy makers have accepted the views of early primatologists, whose work emphasized a link between manhood and male aggression and sexuality, and feminine pursuits and female passivity and nurturance.