THE Book of Genesis had it wrong. In the beginning God created Eve," says Johns Hopkins Medical Psychologist John Money. What he means is that the basic tendency of the human fetus is to develop as a female. If the genes order the gonads to become testicles and put out the male hormone androgen, the embryo will turn into a boy; otherwise it becomes a girl. "You have to add something to get a male," Money notes. "Nature's first intention is to create a female."
Nature may prefer women, but virtually every culture has been partial to men. That contradiction raises an increasingly pertinent question (as well as the hackles of militant feminists): Are women immutably different from men? Women's Liberationists believe that any differences—other than anatomical—are a result of conditioning by society. The opposing view is that all of the differences are fixed in the genes. To scientists, however, the nature-nurture controversy is oversimplified. To them, what human beings are results from a complex interaction between both forces. Says Oxford Biologist Christopher Ounsted: "It is a false dichotomy to say that this difference is acquired and that one genetic. To try and differentiate is like asking a penny whether it is really a heads penny or a tails penny." As Berkeley Psychologist Frank Beach suggests, "Predispositions may be genetic; complex behavior patterns are probably not."
The idea that genetic predispositions exist is based on three kinds of evidence. First, there are the "cultural universals" cited by Margaret Mead. Almost everywhere, the mother is the principal caretaker of the child, and male dominance and aggression are the rule. Some anthropologists believe there has been an occasional female-dominated society; others insist that none have existed.
Sex Typing. Then there is the fact that among most ground-dwelling primates, males are dominant and have as a major function the protection of females and offspring. Some research suggests that this is true even when the young are raised apart from adults, which seems to mean that they do not learn their roles from their society.
Finally, behavioral sex differences show up long before any baby could possibly perceive subtle differences be tween his parents or know which parent he is expected to imitate. "A useful strategy," says Harvard Psychologist Jerome Kagan, "is to assume that the earlier a particular difference appears, the more likely it is to be influenced by biological factors."
Physical differences appear even before birth. The heart of the female fetus often beats faster, and girls develop more rapidly. "Physiologically," says Sociologist Barbette Blackington, "women are better-made animals." Males do have more strength and endurance—though that hardly matters in a technological society.
Recent research hints that there may even be sex differences in the brain. According to some experimenters, the presence of the male hormone testosterone in the fetus may "masculinize" the brain, organizing the fetal nerve centers in characteristic ways. This possible "sex typing" of the central nervous system before birth may make men and women respond differently to incoming stimuli, Sociologist John Gagnon believes.