I didn't have kids because I thought I would be a terrible parent. Always at work, no time or desire to make my life all about all their extracurricular events, no ability to take days off when they are sick. I don't regret it at all. My husband regrets it a little, but he doesn't regret that he didn't have the experience of raising a child, he regrets the "no-one to carry my name or take care of me when I am old" part. I told him once that we could have a kid if he would commit to being Mr. Mom. He wouldn't. Um, there is a guarantee that you have to take care of them, but there is no guarantee they will take care of you when you are old. They might hate you, or have no money, or move across the country to have a life of their own and not want you to move in with them.
Plus, I think cats are a heck of a lot cuter than people at any age. My cat does what I want to do on the weekend (sleep, eat), and she does not join soccer teams or want to take ballet or piano or karate. She is very tidy, and her bathroom is easier to clean than mine is.
And something else interesting - about 75% of my longtime female friends do not have children. Some were in dance and didn't want to get pregnant; some never met Mr. or Mrs. Right and didn't want to do it alone; but a lot of them just didn't want kids.