Wow. And the lead researcher was a scientist and mother who lost her child and didn't like the answer she was given, and decided to find the right one. For those who don't want to dig into the article, there is a defect in the infants' part of the brain (the enzyme butyrylcholinesterase (BChE)) that controls arousal from sleep, so that if the baby stops breathing, they won't awake like others would.