Yes we could all get hit by a bus some day or whatever, but having kids aver a certain age increases the odds of both that you'll die when your kid is young and also that they'll have to care for your geriatric self while they're still young and shouldn't have to worry about it. I think it's plain irresponsible and selfish. If you're 50 when you have a kid (mostly dad's here) you'll be almost 70 by the time your kid even gets out of high school. That's not fair to them.
Also don't you even want to meet your grand kids? And don't you realize you could get sick and die from like a heart attack when your kids are just kids? It kills me that my Dad died when I was so young and he wasn't even old when he had me. I think it's plain selfish to have kids when you're over 40-42.