Transsexuals in Hong Kong are now seeking gender-changing surgery at a much earlier age than two decades ago, and those coming forward are more likely to be women seeking to become men.
"It seems that more and more patients are in their 20s," said Dr Albert Yuen Wai-cheung, chief of service at Ruttonjee Hospital's department of surgery and the only specialist performing sex reassignment surgery at the city's public hospitals.
"In the past, they were in their 30s. Now they are quite young, still studying," Yuen said. "With more information available, more are willing to see doctors."
Also, women undergoing sex change operations to become men now outnumber men wanting to become women.
A spokeswoman for the Hospital Authority said that between April 2010 and August 2011, seven patients - five of them women - underwent sex reassignment surgery at Ruttonjee.
Yuen said he became the city's top authority on sex reassignment surgery "by accident".
After earning his medical degree from the University of Hong Kong in 1979, Yuen won a government scholarship to study plastic and reconstructive surgery in Glasgow and returned in 1987 to Queen Mary Hospital.
At the time, not many doctors specialised in such surgery, he said. Yuen's supervisor at Queen Mary asked him to specialise in the niche area of transsexual surgery because of his expertise in reconstructive procedures.
"Female-to-male is more complicated and involves a lot of reconstructive techniques. That's why my consultant asked me to become involved and that's how I became the first surgeon in Hong Kong to perform female-to-male surgery."
Yuen moved to Ruttonjee in 1992 and today oversees all surgery, but specialises in plastic and reconstructive surgery, which also includes breast augmentations and other treatments.
"This surgery really brings about dramatic changes in the lives of patients and so it is very rewarding," he said.
Since 1987, Yuen has operated on more than 70 patients with gender identity disorder, a condition in which the patient does not accept the gender he or she was born with. Each patient requires up to three operations.
Male-to-female surgery involves breast augmentation, removal of the testes and penis and construction of a vagina. To create the latter, Yuen said, the skin of the penis would be retained and pushed in to line the cavity.
For the female-to-male version, the breasts, ovaries, uterus and vagina are removed. A penis is constructed by stretching the clitoris, and the resulting organ allows the person to urinate, looks like the real thing and is capable of sexual penetration.
"It all depends on what the patient asks for," Yuen said.