Had same argument with my best friend. Granted I was with a girl and fucking around constantly but I don't get how you can't want a kid. My son came a bit early in my life but he is my progeny, my dna lives in him and he gets my amazing brain 
and I get to bring him up and mould him. How can you not want to raise someone like you and teach him and guide him from the fuckups you made?
That is a nice aspect of having a kid, especially if you're lucky enough to have a son. But for me, all the responsibilities and trade offs aren't worth it. Watching my siblings start their families..I know how time, money and energy consuming kids can be. When you have a child unexpectedly, there's no turning back.. you're forced to dive in and make the best of it. I'm sure along the way you discover joys only a parent will know. I'm just making the conscious effort to never have to take that dive. I'm also a realist in the sense that none of my relationships will ever last forever and I don't want them to..life is too short to tie yourself to 1 woman. We all get caught up at times and it can give you some of life's most intense and powerful feelings..but babies and marriage don't ever need to enter the picture.
