I've indeed thought about starting a family, but that would delay any ER plans significantly. That makes me sound very selfish, but that's not the main reason what I am skeptical about marriage. To be brutally honest, I'm not sure if it's worth the potential risk/pain.
Now before you think I'm a cold and unfeeling person, I'm quite the opposite. My biggest concern with marriage is that it can fail -- the odds are against me (and everyone else) at having a successful marriage for life. I know everything is a risk, but I'm not convinced marriage is a risk worth taking. Maybe I just haven't met the right girl yet.
Kids sound wonderful, but that is fraught with risks as well. The best parents in the world can have children who turn out to be horrible people. What if my child dies or becomes permanently disabled? What kind of life-long pain would that bring? I can't imagine it, and the prudent realist in my says the way to avoid such pain is to not expose yourself to the risk.
If everyone was like me, the human race would probably die out in a few generations.