According to a study by Child Trends in Washington, more then 3 million kids in the U.S. under 13 babysit themselves at least a few hours a week. But how do you know if your kids are ready to stay home alone? The laws vary from state to state.

Well, Sherryl Kraizer is the Executive Director of the Coalition for Children. She says that kids under the age of 9 are too young to stay home unsupervised. And if your kids are old enough, but you don't know if they're ready to be on their own, Kraizer says to pay attention to their behavior. If they ask a lot of questions about what might happen if they're alone, it could be a sign of anxiety and immaturity. Also, she says that older kids shouldn't watch their siblings until they're at least in middle school.
And for parents who aren't able to be with their kids as much as they'd like, here's the good news. According to Sharon Vandivere, senior research analyst for Child Trends, letting kids spend time caring for themselves as they get older can be a healthy part of development, and can help prepare them for future responsibilities.