(a) there should be a "Gender" option with free text for selection and not a dropdown menu with predetermined options.
(b) there should not even be a field for it on the profile page. It is common for social forums to have such a field, but...
It is left for everyone to decide on what they wanted to be identified with on the forum, while there is this thing I am more confident in, we can't lie to our own self, if you choose to appear being on this forum as a male, it's your choice, same applies to the other gender, I will only suggest that we leave everything to the usual way it was, because most people don't even pay attention to this aspect, because what matters most is our valuable contribution to the forum growth, except for those that have extra Inter personal relationship with others in doing something whereby gender may be required, competency to me is far more better than gender.