The gist is that like many mammals, babies are born with the ability to hold their pee and poop the same way adults do. When we put diapers on babies they loose this ability and learn to poop and pee freely into their diapers. Then they have to relearn how to hold it again later in life. However if they use this ability in the first six months of life then they can keep it and transition to using the toilet easily. Seems simple right?