Me! (Well, us).
At around 28/29 we said agreed we should probably start trying (we were feeling socially pressured to), but then bought a very expensive property (a once-in-a-lifetime opportunity) that meant us having to hold onto our jobs for dear life. We knocked off a huge amount of the mortgage by the time I was late 30s, had a chat, and both decided that it suited us not to have them. I don't say this selfishly - we both worried about what sort of world we'd bring them into, the cost of having and raising them, and there was also concern in the back of my mind that I could end up being like my mother (a narcissist in the extreme, I had a very unhappy childhood; her mother was the same, as was her mother before her).
I'm now late 40s and do not regret it for a moment. I don't dislike children; I'm a fun aunty apparently, and I love my best friend's boys (twins she birthed at 45), but I'm very happy with my situation. Of course we get people saying how strange it is, intimating there must be something wrong with us, blah blah blah ... I even had a client say "Oh, I'm sorry!" to me when he asked if we had children and I said no. My husband's mother has a real issue with it but that's her problem. I don't feel like I'm missing out, and as my health has seriously deteriorated since I hit 40, I see it as a blessing that we never went there.
I do treat my Labradors like children apparently, and that suits me just fine.