I always put in my bio, "I AM A GIRL." No one really reads bios unless you ask... I sure don't.
I don't think it would be crowded though... on Pirates of the Caribbean online, the group under the name fits perfectly, though it's a bit small. I don't really do groups, but I think this might help the awkward "Oh, you already have a group..." moments. And it would be easier to identify your own group. Some people put the group's initials in their name, and this works fine.
And also I meant under your name-tag that's above your head, not in your bio thingy.