Yet, sexual preferences, genitalia and even secondary sex characteristics, such as facial and pubic hair are first order phenomena. Can genetics and biology account for male and female behavior patterns and social interactions ("gender identity")? Can the multi-tiered complexity and richness of human masculinity and femininity arise from simpler, deterministic, building blocks? Sociobiologists would have us think so. For instance: the fact that we are mammals is astonishingly often overlooked. Most mammalian families are composed of mother and offspring. Males are peripatetic absentees. Arguably, high rates of divorce and birth out of wedlock coupled with rising promiscuity merely reinstate this natural "default mode", observes Lionel Tiger, a professor of anthropology at Rutgers University in New Jersey. That three quarters of all divorces are initiated by women tends to support this view. Furthermore, gender identity is determined during gestation, claim some scholars. Milton Diamond of the University of Hawaii and Dr. Keith Sigmundson, a practicing psychiatrist, studied the much-celebrated John/Joan case. An accidentally castrated normal male was surgically modified to look female, and raised as a girl but to no avail. He reverted to being a male at puberty. His gender identity seems to have been inborn (assuming he was not subjected to conflicting cues from his human environment). The case is extensively described in John Colapinto's tome "As Nature Made Him: The Boy Who Was Raised as a Girl". HealthScoutNews cited a study published in the November 2002 issue of "Child Development". The researchers, from City University of London, found that the level of maternal testosterone during pregnancy affects the behavior of neonatal girls and renders it more masculine. "High testosterone" girls "enjoy activities typically considered male behavior, like playing with trucks or guns". Boys' behavior remains unaltered, according to the study. Yet, other scholars, like John Money, insist that newborns are a "blank slate" as far as their gender identity is concerned. This is also the prevailing view. Gender and sex-role identities, we are taught, are fully formed in a process of socialization which ends by the third year of life. The Encyclopedia Britannica 2003 edition sums it up thus: "Like an individual's concept of his or her sex role, gender identity develops by means of parental example, social reinforcement, and language. Parents teach sex-appropriate behavior to their children from an early age, and this behavior is reinforced as the child grows older and enters a wider social world. As the child acquires language, he also learns very early the distinction between "he" and "she" and understands which pertains to him- or herself."