It has been found that 30 percent of four year olds and 10 percent of six year olds wet their beds more than once a month, occurring more often with boys than girls.
Most children eventually outgrow bedwetting, but it can take some time.
By the age of 12, three percent and age 18, one percent still wet the bed. These individuals are often found to have either a developmental problem or a physical disorder. In the past, it was commonly thought by the parents of bed-wetting children that the child had some type of emotional problem, and frequently, they would blame the child, or blame themselves for having failed as a parent. Being able to sense a full bladder and to control urination depends on the development of the nerve and muscle systems, which does vary from child to child, and may be passed from generation to generation. In this way, bedwetting does tend to run in families, with about 70 percent of children who wet their beds having siblings who are bedwetters, and about 40 percent having parents who had a history of bedwetting.