I got this a lot as a kid. "Someday you'll get older and want kids. No? You're young now, wait and see."
I currently act as a father to several teenagers, and yeah I enjoy it, but popping out my own? Nope, I'm good. There's plenty to go around without my contribution. (My uncle and friend had three kids each. I don't even know.)
What is it that makes people think everyone wants their own biological baby? The cuteness? Because honestly, what is appealing about changing diapers for a year, spending thousands of dollars on medical care, school, food, ect. And when teenagerdom arrives...