Just like a parent can pass down baby blues or broad shoulders, bedwetting can also be inherited from a parent or relative, says Dr. LaRosa. "So if Dad wet the bed until he was ten, you know that little Tommy, who's five, has a long road ahead of him to just let him outgrow it," she says.

There are continued efforts at major children's hospitals to better understand bedwetting. In her book, Mercer says while there isn't one known cause, such factors as sound sleep and inability to wake to a full bladder, small bladder capacity, high overnight urine production, food sensitivities, and constipation play a role.

Bedwetting Alarms 101

Bedwetting alarms sense moisture and alert children, by a loud sound and/or vibration, to get up and head to the bathroom. Typically, a tiny sensor clips onto the underwear and is connected by a cord to a small alarm unit attached to the pajama top.

Mercer says the biggest misconception is that children will hear the alarm. She says at first children often don't wake up for it. She also points out that, according to a 1999 study reported in the Fire Safety Journal, only 15 percent of children, ages six to 17, woke up to a fire alarm. "It's the parent's job to go to the child," says Mercer. "It's behavioral conditioning. Children respond best to their own parents' voices." She says within a few weeks, children generally begin to wake to the alarm, wet spots become smaller, and episodes decrease.

Dr. LaRosa, who reports that a well-prepared child typically sees prompt results, encourages parents to create a sense of excitement, such as counting down the weeks until summer camp or a holiday. She also advises parents to remind their children to empty their bladders before bedtime, even twice; this is known as double-voiding.

"I think the more educated a parent is and the more empowered they feel, the more they will be able to support their youngster rather than be frustrated because they don't know how long it's going to take," says Dr. LaRosa.

Alarms cost about $70 to $90. When Mercer started her practice, she noticed a lack of availability of alarms in the United States. She co-founded www.bedwettingstore.com to make alarms easily accessible for her patients. Mercer points out the cost of just six weeks of disposable training pants cover the alarm cost, adding that unlike with training pants, this is a way to cure.