I have never wanted kids. Almost inevitably the response to that is, "aww, just wait a few years!

" I've been hearing that since I was 12 when I first knew I didn't want kids. I'm now 29 and still as absolutely sure as ever.
One of my reasons is that I simply don't like children. I am averse to holding an infant, definitely do not want to touch a toddler, dislike being hugged by a young child, and have only select children I enjoy talking too, all of whom were lightly brushed by the Autism spectrum. I simply do not look at a child and think, "awww, cute!" My gut reaction is not and never has been one of affection towards that mini-person.
On the flip side, I very much enjoy kids 14+ years of age. Have volunteered with teens for years, and my husband and I will probably someday foster-adopt teens. I'd enjoy the interaction a lot more than if I had to build my own and wait 14 years for them to get interesting. And, while this is perhaps slightly horrible, investing 4+ years in a bunch of kids rather than 18+ years in two strikes me as better odds for eventually liking the resulting adult offspring.
Add to that a health issue I have that has strong genetic predictors, and I'm perfectly happy with my life plans.