I have an airtight argument against evolution, and it's this - children are not built to survive. Any human under the age of 6 is designed to self-destruct without massive amounts of intervention from the older members of the species, so how did the first prehistoric toddlers ever reach maturity?
Seriously, they won't sleep if they get "too tired" and they won't eat if they get "too hungry." If a toddler is left to their own devices, they self destruct due to a combination of self-induced hunger and sleep deprivation. This is, in fact, how nuclear weapons are made. Tired and hungry toddlers are delivered to the enemy and, BOOM, it's all over.
When they're not making noise, they're fidgeting. When they're not moving, they're noisy. They might as well have a steak tied to their necks and a neon sign that says "Hey Saber-toothed tiger, I'm over HERE!" on their back.
They have huge, fragile heads and itty-bitty feet. And this disproportion peaks at about the age they start walking. In fact, that's how you know when they're going to start walking. Their heads swell and their feet shrink. Now I'm no archeologist, but I don't think we've found any cave drawings of helmets yet, so there was no way they had any protection.
And there's no way any human tribes with small children ever migrated over long distances. Have you ever tried to take a 4 year old hiking? They're too heavy to carry, and too slow to walk. And when they turn 5 it gets worse, because now they stop every five minutes to investigate something shiny. I don't know how you say "Are we there yet?" in grunting, but I bet a mass migration would result in two-thirds of the children being thrown into a saber-toothed tiger den.
Too little to throw a spear. Too oblivious to gather nuts and berries. Kids weren't designed for the hunter-gatherer lifestyle. We must have been created as adults in a nice, cozy garden because otherwise the kids wouldn't have made it and the species would have died off! This logic is airtight.
P.S. I'm being facetious on many levels. Please don't start having conniptions over this. :)