I don't want kids.
I mean, I don't think I do. It doesn't make logical sense to me to have one when the world is so crowded as it is. I also worry that they'd just grow up into an arsehole, or like sports or something.
Sometimes, though, I like to think about having a child and then performing weird experiments on him/her. Nothing crazy or anything- just something like never informing them about Santa or the Tooth Fairy, and waiting all that time for them to come home from school one day, freaked out that other people believe that kind of stuff.
If I manage to trick someone into marrying me, and she really wanted kids, then I'd happily adopt. But I don't think you're allowed to play mind-games like that with adopted kids, so my fun would be ruined.