Babies need a lot of sleep. Some of them need as much as 16 hours a day, if naps are included. But even when they’ve made it to 12 months, nearly half cannot stay asleep for eight hours without waking. However, there’s no need for alarm: there’s a simple reason that babies can’t sleep through the night.
For sure, babies are born with an idea of time. They gain it from the womb’s rhythms and from mom’s distant heartbeat. But above all, they each inherit genes that control sleep. These genes are not something that the baby can ignore: all babies will sleep. They all also have another group of genetic instructions that will help them establish a circadian rhythm.