With such a seemingly infinite number of gender identities in the spectrum, I think it would be hard to figure out what else to offer without anybody feeling slighted. There's always been the option to not choose either male or female, and we can always add our particular gender identity to our profiles.
This has come up before. The only reason the gender field was added was because of the "covens" which were really meant to be just special interest "groups" but I thought I'd have some fun and call the groups and call them covens and everyone took the word literally so the whole group thing fell by the side. Anyways, while researching coven leadership, it was common to have a female and male leader be the priestess and priest of hte coven, so again I though, wouldn't it be fun to do that here with the leadership.
So long story short, the way we record gender can't be easily changed without having to rewrite a bunch of coven leadership code