Dilemma

So I went to the OUTFront Action meeting tonight, and it was good, though a little more just-getting-started than I was hoping. (for those who have never heard of this group, like me until 2 days ago, it's sponsored by Amnesty International and specifically focuses on LGBT human rights) So anyway, it was good, but here's my dilemma - the group made the (fairly obvious and expected) assumption that I'm gay. Which is fine, except that telling them I'm straight seems like making it a big deal (which it isn't) and not correcting them seems deceptive. Suggestions on what the appropriate action might be?