Boards
Unprotected sex.
I don't want to be too crude about this, but have you ever had it? Obviously it's deliberate in many cases, but I'm sure there are a lot of people who just didn't use contraception. So why did you do it, did you just forget? And who with, was it a one night stand?
Also, perhaps more importantly; to the females.. Did you take morning after pill? How easy is it to get, are there any side effects, etc? And if you didn't, why not?