It is increasingly dangerous to have a child past 30. The danger is most pronounced for older women. If you want a family, I think the time for the bootstrapping raman startup has passed.
That risk is not pronounced past 30, but 35. Adding to that, it negligible. It's not like 50% of babies have issues, it's just that a greater percentage do compared to women in their 20's.
Most families these days are started by parents in their 30's.
I wouldn't even consider starting a family later than 35. And look at 45! More than a 1 in 33 chance you will have a child with Down syndrome (Trisomy 21) after 45...those are definitely not gambling odds.
Those numbers are far too small to base such a life changing decision on.
And this kind of risk to the baby is not nearly as serious as a risk to the mother. You can always try again. These are the stats you should be considering.
This is only an issue for women. Risk of problems with pregnancy (and birth defects) goes up significantly for women as they get older (best time to have kids for women is in their 20's). The male reproductive system is much, much simpler though and I don't think age is a factor for men at all. Of course as you age you'd have to find someone increasingly younger than you to carry a child. That would be the only problem.
On the other hand some men would not consider that to be a problem at all (assuming you can find a mate). And if you're a 40 yearold millionaire you shouldn't have a problem finding a 20-something to have a kid with. :-)