I'm all for not asking for gender information in the first place. It's completely irrelevant in all but very few situations. Ending up in bed with someone who has different bits than you expected, is awkward. Everything else is just pointless.
The only real reason why computer systems ask for gender information is so they can address you "properly". Some languages have neutral pronounds (their, them, etc) for that, others don't. If your users are using a language where this doesn't exist, tough luck for them. I'm sure every language at least has some kind of rule (ie "use male pronouns when in doubt") of dealing with these situations.
My Facebook profile at least has the option of not showing my gender, even if it doesn't let me select Other or NoneOfYourDamnedBusiness.
The only real reason why computer systems ask for gender information is so they can address you "properly". Some languages have neutral pronounds (their, them, etc) for that, others don't. If your users are using a language where this doesn't exist, tough luck for them. I'm sure every language at least has some kind of rule (ie "use male pronouns when in doubt") of dealing with these situations.
My Facebook profile at least has the option of not showing my gender, even if it doesn't let me select Other or NoneOfYourDamnedBusiness.