Hmm... I generally percieve children as scary, since I'm unsure of how to communicate with them. I think it's going to take a few years (about 15 or so) before the concept even starts to not seem repulsing. (Not to mention I'd be a horrible parent.)
I understand the people who don't want kids. It is a daunting responsibility, and if you feel that you're not up to the task, odds are you're probably right. I don't see how it could possibly be selfish, unless you're together with someone and they want kids. That's where discussions come in handy.
If it's selfish to want children... hmm... I suppose generally no, but if you don't take care of them properly the option really shouldn't have been contemplated in the first place.