What's strange (sad?) is that I am most definitely adult age but, being someone who lives in NYC and works at a startup, my mindset was "I wonder what I'll do when I'm at that age?"...I guess I'm qualified to answered: for me, not having kids now is not different than not having kids in college. Not enough philosophically about my life (marital status ir probably the key one) has changed since then. Very few of my friends, the same age or older in NYC, have children either. And my guess is that this state of affairs could exist for years to come until suddenly I'm thinking, "I wonder if I should've tried to have children?"