Dear Grandparenting: It all changed after my grandson discovered sex. Everything went fine until he hit 15. Then he turned into something else.

He started doing just what he pleased instead of listening to his mother, who happens to be my dear daughter. He started bringing around girls that have bad reputations, sometimes two at a time. When his mother is away at work, he carries on right in front of his sister.

This has been going on for some time now. We tried being patient, thinking it would pass. Last week he told my daughter he had a sex addiction.

That’s a new one on me. My grandson thinks he needs treatment, whatever that means. My daughter likes that idea. Since I’ll be the one who pays the bill, is this just nonsense or what? Maggie Blevins, Columbus, OH

Dear Maggie: Sex addiction sailed onto our radar when cheating celebrities like Tiger Woods began signing up for treatment to curb the urge. But is it just an excuse for bad behavior, or an actual addiction that makes it difficult to manage one’s sexual behavior?

Medical professionals are divided on the issue. The Diagnostic and Statistical Manual of Mental Disorders — the bible of the mental health community — does not include sex addiction due to a lack of research.

But the American Society of Addiction Medicine, the largest group of physicians dedicated to treating addiction, acknowledges sexual addiction as does the World Health Organization.

Treatment generally involves psychotherapy, medication and self-help groups. But we’re getting a little ahead of ourselves to talk about professional help just yet.

Your grandson may desire treatment because it confers certain bragging rights in today’s sexually obsessed society. Perhaps the problem is attributable to the glut of Internet-based explicit sexual content. An absence of adult supervision is a probable cause, since he evidently lives in a single-parent household.

Read your grandson the riot act regarding acceptable behavior and hold him accountable. The hallmark of addiction is an inability to control oneself, so put all options on the table should his behavior persist.

GRAND REMARK OF THE WEEK

M.C., from Marshall, Michigan, was surprised to learn that her sister in California was considering cosmetic plastic surgery.

“Who needs plastic surgery,” she told her, “when you have grandkids to keep you young?”