I'm not married, don't have kids and I don't really want kids. If I ever get that maternal urge, I think I would rather adopt than have biological children--for the same reason Jen mentioned (I don't need to contribute to the overpopulation of the planet).

I don't want kids because I want to have a career and be free to travel if I want to. I have very specific ideas about how kids should be raised, and I'd have to stay at home with my kids until they were school-age...I wouldn't want a day care or nannies raise them. Because I'm not willing to raise kids in the way that I think is the "right" way, and because I'm covetous of my free time, I'm just not going to have any. That said, I'm so willing to be the fun aunt and spoil my siblings' future children . I like kids, just in small doses.