To me, cases like that really scream out, ‘Hey, it’s not out there. It’s in here.’ There’s no indication that this mother is prone to raise very femi… - J. Michael Bailey

The fact is that we don't know enough about hormonal effects on the human brain to have a very specific theory of how Danny's brain could have developed in a feminine direction while his body developed masculine. If Danny's body also showed signs of feminine development, this would support nature theory, but the lack of anatomical femininity does not disprove it. There has been essentially no research on boys like Danny that is directly biological. Short of dissecting the brain of a feminine boy and comparing it with normal boys' and girls' brains, it is unclear what we would even look for. However, the best conceivable direct test of nurture theory has been tried, and it failed. Amanda became Jason again.

In order for a feminine boy to become transsexual, something extra must happen. What is the something extra?

Nobody ever gave Danny Ryan a dress before he asked for one, and he was punished much more than rewarded for his gender nonconformity. If he grows up to be a gay man, as I expect he will, it will be despite the most obvious influences in his social environment, not because of them. In the short term, Danny will receive no more encouragement from others to become gay than he did to wear dresses. Behavior that emerges with no encouragement, and despite opposition, is the sine qua non of innateness. Boys like Danny are poster children for biological influences on gender and sexuality, and this is true whether or not we measure a single biological marker.