01gt4.6 - Theres a certain level that kids take over from their parents. For me against my dad at squash it was around 16/17yrs old, but I haven't played for some time so that old timer would probably beat me these days (quite comprehensably). But generally around 20-25 yrs old children will surpass their parents in physical abilities. Obviously this isn't scientific, a hardcore 16 yr old beats an unfit parent and a fitness freak parent beats a 25yr old kid, etc. but that is the age that I've seen it happen at the most.
When I'm a parent I'd be quite pleased to see my son/daughter surpass me, I don't know why you're so amped to beat them?
If there hadn't been women we'd still be squatting in a cave eating raw meat, because we made civilization in order to impress our girlfriends.