The report found that babies who don't sleep well may be programmed to be that way.
After studying 1,000 twins, experts concluded that sleep patterns are primarily based on genes.
But there's good news. By 18 months of age, environmental factors such as a bedtime routine will start to play a role in how well the baby sleeps.
Experts say that's the best time to try to manage sleeping habits.
As for napping, the study finds that children's daytime sleep is strongly influenced by their environment rather than their genes.
