Since going to sleep means separating from the people they love, bedtime can be scary or stressful for some young children. Your baby is figuring out how to comfort himself to sleep -- in this case, by sucking on the blanket -- which is an important accomplishment. Feeling "I can this do for myself" builds a child's self-esteem and sense of security during the wild and wonderful toddler years.
If this kind of behavior is new, think about whether there have been any recent changes in his life. A different sitter or daycare, or anyone he's missing? Is he on the verge of a major milestone, like walking? Children often experience anxiety about a big developmental step and will regress in other areas, becoming more clingy or waking up during the night. It could also be that your baby is having some separation anxiety and the blanket has become a substitute for your love and comfort when he can't be with you.
Whatever the reason, consider this blanket a real asset for both of you. If your baby ever needs to sleep away from home, having his blankie will make the transition a lot easier. And rest assured, your child will not be attached to his blanket forever. Children give up these kinds of behaviors as they get older and find other ways to soothe themselves.
Originally published in American Baby magazine, November 2004. Updated 2009.