Many states have enacted or contemplated limits or outright bans on transgender medical treatment, with conservative U.S. lawmakers saying they are worried about young people later regretting irreversible body-altering treatment.

But just how common is regret? And how many youth change their appearances with hormones or surgery only to later change their minds and detransition?

Here's a look at some of the issues involved.

WHAT IS TRANSGENDER MEDICAL TREATMENT?

Guidelines call for thorough psychological assessments to confirm gender dysphoria -- distress over gender identity that doesn't match a person's assigned sex -- before starting any treatment.

That treatment typically begins with puberty-blocking medication to temporarily pause sexual development. The idea is to give youngsters time to mature enough mentally and emotionally to make informed decisions about whether to pursue permanent treatment. Puberty blockers may be used for years and can increase risks for bone density loss, but that reverses when the drugs are stopped.

Sex hormones -- estrogen or testosterone -- are offered next. Dutch research suggests that most gender-questioning youth on puberty blockers eventually choose to use these medications, which can produce permanent physical changes. So does transgender surgery, including breast removal or augmentation, which sometimes is offered during the mid-teen years but more typically not until age 18 or later.

Reports from doctors and individual U.S. clinics indicate that the number of youth seeking any kind of transgender medical care has increased in recent years.

HOW OFTEN DO TRANSGENDER PEOPLE REGRET TRANSITIONING?

In updated treatment guidelines issued last year, the World Professional Association for Transgender Health said evidence of later regret is scant, but that patients should be told about the possibility during psychological counseling.

Dutch research from several years ago found no evidence of regret in transgender adults who had comprehensive psychological evaluations in childhood before undergoing puberty blockers and hormone treatment.

Some studies suggest that rates of regret have declined over the years as patient selection and treatment methods have improved. In a review of 27 studies involving almost 8,000 teens and adults who had transgender surgeries, mostly in Europe, the U.S and Canada, 1% on average expressed regret. For some, regret was temporary, but a small number went on to have detransitioning or reversal surgeries, the 2021 review said.

Research suggests that comprehensive psychological counseling before starting treatment, along with family support, can reduce chances for regret and detransitioning.

WHAT IS DETRANSITIONING?

Detransitioning means stopping or reversing gender transition, which can include medical treatment or changes in appearance, or both.

Detransitioning does not always include regret. The updated transgender treatment guidelines note that some teens who detransition "do not regret initiating treatment" because they felt it helped them better understand their gender-related care needs.

Research and reports from individual doctors and clinics suggest that detransitioning is rare. The few studies that exist have too many limitations or weaknesses to draw firm conclusions, said Dr. Michael Irwig, director of transgender medicine at Beth Israel Deaconess Medical Center in Boston.

He said it's difficult to quantify because patients who detransition often see new doctors, not the physicians who prescribed the hormones or performed the surgeries. Some patients may simply stop taking hormones.

"My own personal experience is that it is quite uncommon," Irwig said. "I've taken care of over 350 gender-diverse patients and probably fewer than five have told me that they decided to detransition or changed their minds."

Recent increases in the number of people seeking transgender medical treatment could lead to more people detransitioning, Irwig noted in a commentary last year in the Journal of Clinical Endocrinology & Metabolism. That's partly because of a shortage of mental health specialists, meaning gender-questioning people may not receive adequate counseling, he said.

Dr. Oscar Manrique, a plastic surgeon at the University of Rochester Medical Center, has operated on hundreds of transgender people, most of them adults. He said he's never had a patient return seeking to detransition.

Some may not be satisfied with their new appearance, but that doesn't mean they regret the transition, he said. Most, he said, "are very happy with the outcomes surgically and socially."