It's the amygdala, which is inner brain and multifunctional. Endanger your kids, guys. Gently! Let them climb trees so high they might break their leg. Take them rock climbing.
Peril during childhood is essential to healthy amygdala growth. Without peril, they will fail to identify actual threats while feeling existential panic over purely ideological threats. I'm saying they'll turn into liberals.
Fluoride as well