My DH and I don't have kids and people stopped asking a while ago.....most likely because I am going to be 45 and my Dh will be 48...GULP...did I just put that in writing
This is the second marriage for us both and when I was younger, I "thought" I wanted kids because it was the thing to do right....get married, have kids...
It just did not turn out that way. Instead I was married the first time for 1 year. I was married at 21 and divorced at 22. I did not get married again until I was 39! The time in between was filled with great jobs, lots of fun and travel and a hot guy or two

Yes I had fun with a capital F. During that time my friends were getting married and having kids...so along with that came the prefix to when are you having kids which is "when are you going to settle down"? Which IMHO is even worse that the kid question. My friends lived vicariously thru me. Their big "escape" was to come to my apartment and have coffee. I always knew I wanted a different kind of life and I would meet someone just like me...and I did.
My DH and I have been married for 5 years (he does not have children either) and we are very happy. We have been able to do things and take risks financially that we would not have been able to do if we had children. We own our home, have our own business - (that was the financial risk we took) We travel a lot for fun - we just returned from a 3 week long vacation, and have 4 more to go for this year. Our business does not require a store or employees, just a laptop and cell phone. We go out for romantic dinners often, drive very expensive cars, go to the beach on nice days,we have everything we want. My day starts with my DH making juice and we are off to the health club where I have a personal trainer. We are never bored, even though it is like we are semi retired. We live close to NYC, so we go when we want or go to the beach on a nice day or to the mall and buy stupid stuff or out for a great lunch. We have a great family and lots of friends. Our life is full and rewarding, but that is waht works for us. We are also extremely generous to our family friends and charity. We live a great life, and I know if we had children to think about their needs would come first and we never would have been able to make the decisions we did to get where we are.
I do not think we are selfish or self centered. I think some people have children for all the reasons. It is not that I don't like kids, I just don't like the idea of being a mother at this stage of my life. I know in my heart and soul that I would not be able to deal with play dates, soccer, karate, dance, religion class, teacher meetings, homework, softball, baseball, brownies, girl scout cookies, science projects, doctors, dentists well you get the idea....
Having kids does not gurantee you grandchildren, or a great family or security when you get older.
So as I see it, people should just mind their own business. They made their choices in life, now it's your turn. No matter what you choose all that matters is that you are happy and fufilled.
Also, we love the fact that we look 10 years younger than our real age....I think it's because we don't have kids
So that is my long tale of why I don't have kids. I know it's longer than some, but I am older!