Is he an overall immature 23 year old? I'm assuming this a guy you are with and you want children....soooo you are wondering if you should get out now right?
It depends why he doesn't want children. If he is one of those that thinks bringing a child into the world is an act of cruelty, then most likely, his view will not change when he is 30. If he doesn't want kids because he doesn't want to be tied down, or he has some wild oats to sew or something, then I'd bet his view will change when his biological clock starts ticking.
To be honest though, all the guys I've known that didn't want children, were pretty steadfast in their ways.
Hybrid Mode
