My job has made me into a TBI truther. Brain injuries are devastating to cognition, self-regulation, and a bevy of other health outcomes. It's linked to a zillion bad social outcomes.
Forget about every other factor that determines human development outcomes: forget about genes, IQ, pollution, whatever. All of that shit is easily washed out by one good fall off of a bike. But unlike genes, we can actually do something about protecting brains.