Q. Our 3-year-old son has been day and night potty trained for nearly a year. Several months ago, just after starting pre-school, he wet the bed a couple of times. A friend with older children advised us to spank, and one spanking stopped it. Then, however, he started to wake us up in the middle of the night, saying he needed to use the potty. I told him to stop waking us up, and he stopped, but then he started wetting the bed again.

Our 4-year-old nephew wets the bed every night, and his parents were told by a therapist that it was a way of controlling them. Could our son be wetting the bed as a way of controlling us? In any case, what's the best way to solve this problem?

A. The friend who told you to spank gave you very bad advice. And the therapist who told your nephew's parents that bed-wetting is a control issue is wrong. Your nephew may be in control of the parent-child relationship (most kids are these days), but bed-wetting is most certainly not one of his weapons.

Wetting the bed at age 3 is no cause for concern. The mere fact that your son was dry at night for nearly a year after he was toilet trained doesn't mean he can control his bed-wetting. No one knows why, but boys have more of a struggle with this than girls. For every 3-year-old girl who is still wetting the bed, there are four boys. Furthermore, it's not unusual for a child who's been dry at night for a significant period of time to suddenly begin wetting.

Punishment will not correct this problem and may well make matters worse — much worse. Bed-wetting is linked to deep sleep. The best explanation is the child sleeps so deeply that he doesn't sense that his bladder is full. Consequently, instead of "holding" or getting up and using the bathroom, the child wets the bed. Furthermore, he may continue to sleep through the night on sheets that are soaked.

A change in routine often precedes the start of bed-wetting. My son Eric wet the bed for a short time after we moved from Illinois to North Carolina when he was 5. Your son started wetting, not coincidentally, shortly after he started school. Being in school during the day may wear him out, causing him to sleep more deeply than before. Thus, he wets the bed.

If you concern yourself with more important things, and let time take its course, this little glitch will probably resolve itself within a year. On the other hand, if you want to help a solution along, you can purchase one of the several bedwetting alarm systems sold online at www.bedwettingstore.com, or call (800) 214-9605.

These systems are not intrusive, and the set-up is not complicated at all. In some cases, however, the manufacturers don't tell you that the child usually sleeps so deeply that he doesn't hear the alarm (signaling he's wetting) at first. For a few nights, when the alarm goes off, the parents need to wake the child and "put him through the paces." Your pediatrician may also have access to a similar system which he'd rather you use, so check with him first. But your frustration and anger will only worsen things.

Family psychologist John Rosemond answers parents' questions at www.rosemond.com.