This is not gonna work
even if you have such button and even if you ignore the fact that 50% of girls are actually guys playing girls. the worst of all is that 50% of those remaining girls will be pretty hostile towards guys and if she is actually responding nice that is probably a guy.

The main problem is big imbalance between number of available girls and guys and also severe mismatch of their interest.

If you don't mind anonymous dating you can try F-list but it does not allow any real life information sharing and you can get banned. Most people will not share any information either way unless they are guys. (and that's actually good, because real girls happen to be not that good looking as their profile pictures ) either way your girlfriend will be living on the other side of the globe so meeting her will be next to impossible.

>>8876
Not necessary so.
situation goes like this:
you register on some website as a guy, try to approach some good looking girls they send you go fuck yourself. then you create super attractive female profile and approach girls as lesbian or pretend to be a girl when interacting with guys as kind of role play.

In fact everyone is practically required to have male and female profile or even several of them just for scientific purposes as to get an idea how does it feel being opposite gender and learn how to interact with them.
Being yourself online is not that good idea, because very often people will be hostile or ignore you because you have wrong gender. but they will be pretty nice to you if you have right gender.