Though bedwetting can be a symptom of an underlying disease, most children who wet the bed have no underlying disease that explains their bedwetting. In fact, an underlying condition is identified in only about 1% of children who routinely wet the bed.
That does not mean that the child who wets the bed can control it or is doing it on purpose. Children who wet are not lazy, willful, or disobedient. Bedwetting is most often a developmental issue.