In the majority of cases, the child’s biological sex matches their gender and there are no problems. However, some children are born “inter-sex”; they have ambiguous genitals and are not obviously one sex or the other. Money believed that, providing that a a child’s sex is decided before their 3rd birthday, social factors are so influential that children will accept their assigned gender identity.
The third year is another critical period, and because a child’s gender identity is established by then, it cannot thereafter be changed without causing the child significant psychological problems.
Early research did support this hypothesis. Goldwyn cites the case of Mrs DW, who had androgen insensitivity syndrome, but was brought up as a woman. When informed that she was biologically male, she felt that she was a woman and elected to remain that way. This shows that social factors strongly influence our gender identity; more so perhaps, than our biology. This therefore supports Money’s hypothesis that social factors determine gender identity. This however, is a case study. Although it provides rich, detailed data, it is essentially a sample of one, so the results cannot be extrapolated elsewhere.
Although the case of Mrs DW provides strong evidence for Money’s theory, another case study by Colapinto contests it. David Reimer was raised as a girl following a surgical accident in which his penis was damaged. Unlike Mrs DW, David was uncomfortable in his