A British Web site, Manboobs.co.uk, welcomes readers with the slogan, “Welcome to Man Boobs. The site that says, ‘we’re fat and we’re proud,’ and then quickly puts it T-shirt back on.” And several Web sites, such as gc2compression.com and makemeheal.com, sell compression garments that purport to reduce the visibility of enlarged male breasts.

Plastic surgeons in the United States suggested that the rise in popularity of professional golf may have also contributed to public awareness of gynecomastia; several prominent popular players have slightly enlarged chests.

But in most adolescents who are not obese, the condition will resolve itself spontaneously as the boy progresses through adolescence and produces more testosterone, said Dr. Brenda Kohn, an associate professor of pediatrics who specializes in pediatric endocrinology at New York University School of Medicine.

As such, she said, “It is very important that one not operate on a child who is still in puberty.” If surgery is done too early, she said, the hormones that caused the initial breast enlargement may still be active and cause ongoing breast development after surgery.

While gynecomastia in young men is most often associated with hormonal fluctuations or obesity, many surgeons are also beginning to link it with increased abuse of steroids. “They have hopped up their testosterone levels, and so when they get off the stuff, there is a change in the hormonal milieu,” said Dr. Guy, the Florida plastic surgeon. “It can reset itself, but many times if they have abused steroids, you have to send them to an endocrinologist to address the problem.” If that doesn’t work, she said, they come back to her for surgery

Surgeons who are referred a young patient by a pediatrician often will first call for a complete endocrinological workup to make sure that the breast enlargement isn’t a transient hormonal fluctuation. Other causes include decreased testosterone production, kidney failure, testicular tumors and liver disease. The condition can be addressed with hormone treatments such as testosterone patches or even Tamoxifen, an estrogen-inhibiting drug that is best known for its use in the treatment of breast cancer in women. “You have to rule out any other cause before surgery,” Dr. Copeland said. (This reporter was until four years ago a cosmetic surgery patient of Dr. Copeland.)