Aramis Night said:
Biology did create the original social conditioning, and the chemical broth that men and women are individually subjected to create very different minds. However, I would argue that social conditioning plays a huge role. Humans have not evolved very much in 1,000 years (as evolution takes a much longer period of time), yet society has changed immensely over that time period. If human social factors are mainly caused by biology, then society should be more or less the same (with the exception of an ever rising level of technology). And this is certainly not the case.
We can also see the importance of social conditioning through various cultures. Tribes in Eastern Africa, for example, have a rite of manhood in which severe scarring is done to the back in order to imitate the scales of the crocodile. Self-injury is completely against every natural biological instinct, yet the people regard it as a point of pride to receive such scars. That is, the social pressure of attributing manliness to this scarring overcomes the biological urges of self preservation (not saying that this scarring is bad, just using it as an example).
And I agree with the fact that no person can "decide" for another person whether they should indulge in his/her own nature. However, that choice is currently being made for people. Girls are encouraged to do girly things, while boys are encouraged to do manly things. Girls are supposed to be sensitive and caring, while boys are supposed to bottle up emotions and compete with one another. While these undoubtedly do have biological roots based on the chemical facts of testosterone and estrogen, society amplifies their effect. Driven by images and a social standard of "beauty," women are driven to starving themselves far beyond what is biological healthy (or even biologically attractive). Driven by social standards of scoring=manliness, men spend tons of effort to pursue and sleep with women. While desiring sex is biologically driven, the social stigma of being a male virgin (or a female non-virgin) is definitely not.
By declaring a gender neutral term, the government can reduce these effects, or at least provide an optional identity. However, whether or not this will be effective at all will have to be seen.