I'm 41 and my boys are 4 and 8. It's wild to even consider I could have been a grandfather by now if my life choices had been different. Wouldn't be such a bad thing though, at 40 you're still pretty young so I could've had my freedom back by now. As it is I'll be 55 by the time they're out of the house and probably won't be able to pick mountain biking back up...

And then if they wait a while I could be pushing 70 before my grandkids arrive. Great-grandkids might be a relic of a time gone by...