Because an infant’s brain isn’t being “rewired”, it’s being built and is in a foundation state of architecture. This doctor seems blind to the reality that our brains grow and develop most after birth — this is the entire argument behind the science of why human babies are born so helpless compared to most animals — so our big brains can grow after birth instead of tearing up our mothers during birth. Logically it follows if we believe babies brains grow more after birth that our brains are not formed or wired yet at birth.