He said transsexuality was so taboo in the former Yugoslavia that it was not even mentioned in medical textbooks. But a surgeon, Dr. Sava Perovic, began performing the operations in 1989 after being approached by a man suffering from gender identity disorder.

Word quickly spread and Dr. Perovic, who has since died, attracted a legion of patients, as well as fellow surgeons drawn by the challenge of an exceptionally difficult procedure. More than 20 years later, sex reassignment surgery has become a surprising niche here, with four medical centers specializing in the procedure.

In Serbia, the surgery is performed in a single six-hour procedure, saving the patient from the trauma of multiple operations. Complications can include postoperative regret, functionality problems or infection.

To qualify for the surgery, a patient needs two letters of recommendation from psychiatric specialists attesting that he or she is suffering from gender identity disorder, in which a man or woman identifies better with the opposite sex. At least one year of counseling and one year of hormone therapy are required before the surgery.

Daniel, a 25-year-old lawyer from St. Petersburg, Russia, came to Belgrade in May for the surgery after he said he failed to find a suitable surgeon in his country. The surgery and treatment have been so successful that Daniel, who lifts weights regularly and likes to sport facial stubble, betrays few signs that he was once female.

Asking that his last name not be used for fear of being hounded back home, Daniel said he had known since he was 10 that he was male in a female body. When he was 18, he said, he told his family that he was a lesbian, even as he realized that physically becoming a man was his ultimate goal. He said his grandparents, both physicians, refused to accept it, saying he had a disorder of the brain.

“I came out twice, first as a lesbian, then as transsexual. That made it easier,” he said a day after having the surgery. “Russia is extremely homophobic, and coming to Serbia was easier for me.”