>>15429
You mean without that trait, right? Because it's those who didn't kill themselves as children that get to pass their genes down, so eventually less and less children would tend to kill themselves.
Yeah, I didn't think that deep, but since it's fantasy anyway, we can always imagine it's a purely social thing and not in the genes.
At some point the society just starts expecting to see children die every so often, have snuff festivals at schools and such, keeping the death rate stably high.
Then there's also social evolution, but I think in a world with unlimited resources it just means societies that kill more children will just grow slower, but as long as they birth more children than they kill they can still grow.