"There are a few things that should be off-limits though:
Race, gender, sexual orientation, religion, place of birth, etc."
Err, despite being politically incorrent, using religion and place of birth is probably a good idea.
How many Buddhists have blown things up? How many Taoists?
How many Christians? How many Muslims?
How many people born in Canada have gone abroad to blow things up?
How many people born in the middle east have gone abroad to blow things up?
Hell, given that most of the bombings are religiously motivated, and most religions don't tolerate gays, you could probably just clear most homosexuals right off the bat without worry.
Anyways, political correctness is stupid, blah blah blah.