Hi, i am in the final stages of building my site and i am allowing users to sign up to my site using Facebook and Twitter, however i have just noticed that Twitter do not know / record your Gender, which is a requirement for my site...

My service needs to know your gender in order to work.

Question:

Should i remove the "Signup With Twitter" option or should i look at some way of getting the user to select their Gender after the join... thanks in advance