Few people know it, but one of the world’s busiest gender surgery clinics is located in a non-descript building in Montreal.

For at least two decades, it's been the place where people from around the world with gender dysphoria come to make the final permanent changes that will transform them. 

CTV News was granted rare access to the GRS clinic and its chief surgeon, Dr. Pierre Brassard.

"It is a rewarding practice," he said on a typically busy day that included four vaginoplasties, (surgical constructions of a vagina), and one phalloplasty (the construction of a penis).

Dr. Brassard said he conducts more than 650 gender surgeries a year. The clinic is the only one in Canada that offers gender reassignment surgery.

Brassard's waiting list is over six months long, but he expects that list to grow longer now that most provinces provide some form of health coverage for his services.

"I think we're probably the biggest, certainly in North America," he told CTV News, adding that he's had clients from North America, Europe and Asia.

Brassard has built a strong reputation for his work over the last two decades, with one of his most high profile clients being Jenna Talackova, a former Miss Universe Canada contestant.

Another patient, 23-year-old Edith Turrubiate, began life in Texas as Eduardo. She said she preferred dolls to trucks, but her parents urged her to act like a boy and “do what your dad does.”

She said her childhood set her up for an adolescence filled with pain and confusion.

“It had something to do with feeling disgusted, not being able to understand,” she told CTVNews.

At 16, Turrubiate began her long journey to become a woman, using hormones at first.  She saved up to get gender surgery in Montreal when she read about Dr. Brassard's reputation.

"Without the surgery I wouldn't be able to go on living, having that feeling of strangeness," Turrubiate said.

Turrubiate had to pay for her surgery out-of-pocket because she is American. But most provinces now cover gender reassignment surgeries for those who have been diagnosed with gender dysphoria (feeling like one is emotionally or psychologically opposite from their biological sex).

Suicide rates remain high among transgender youth. A 2015 survey of 900 transgender individuals between the ages of 14-25 found that more than one-third of them had considered suicide at least once.

Dr. Brassard said he's glad he can ease the pain for those who struggle with their identity in that way. "You change something very important for them."

With a report from CTV's medical specialist Avis Favaro and producer Elizabeth St. Philip