Like many other surgery patients, Hayley Anthony has a daily physical therapy regimen. But unlike other post-ops, the 30-year-old marketing consultant is recovering from a procedure she helped invent. Five months ago, she became one of the first people in the world to have a piece of tissue incised from the cavity of her abdomen and turned into a vagina. A surgeon in New York City may have pioneered and performed Anthony’s procedure—but the idea to try it in the first place was all hers.

With only about a dozen doctors in the US who specialize in gender affirmation surgery, it’s nearly impossible to keep up with demand, let alone innovate new ways of doing things. But that’s what Jess Ting, director of surgery at the Center for Transgender Medicine and Surgery at Mount Sinai, has been up to for the last two years. What started as a Google search on Anthony’s computer is now the most sought-after surgery Ting performs. In the last six months he’s given 22 trans women something that they weren’t sure they’d ever have—a vagina that looks and feels and secretes like the real thing.

Anthony had known her whole life that she was female, but she didn’t begin transitioning until about four years ago. Then, in the fall of 2015, after months of working with a therapist to better understand herself and her options, she accepted that she had to do whatever it took to have the right body for her mind. She scheduled a consultation with Ting and they made a date to make her a new vagina. Then she went home and down a deep internet hole. “I had gone into the process, eyes wide open, understanding all the compromises and willing to accept them,” Anthony says. The procedure she was mentally preparing for involved slicing open the penis, removing most of the inside parts, and then folding the penile skin into the space between the urethra and the rectum (kind of like turning a sock inside out). In what has become the standard surgery for a male to female bottom transition, the outside of the penis then becomes the inside of the vagina.

But a vaginal cavity made out of skin doesn’t do some things the inside of vagina should (like get wet when aroused) and does others it really shouldn’t (like grow hair, even after electrolysis). For trans women with genital dysphoria, it’s been the only real option for bottom surgery, and it’s been a pretty good one. But the procedure can still leave many disappointed.

During her research though, Anthony came across a paper describing the work of some doctors in India who were building vaginas a bit differently. They were performing surgeries on women with a rare disorder that causes the organ to develop abnormally or not at all. So they had to start from scratch, which requires a lot of material. They found a way to do that with tissue from the peritoneum, which is basically a bag of loose tissue that encircles the inside of your abdomen and holds your guts in place. She brought the paper into her next consultation and showed Ting. “At first he was like, ‘What is this girl doing?’” Anthony says, laughing. “I have no medical training. I’m not a scientist. But then he looked at it and said, ‘Oh, there might be something here.’”

Surgeons have tried before to harvest other parts of the body to make more vagina-like vaginas for trans women. About 10 years ago some doctors attempted the procedure with small portions of patients’ colons. That didn’t work out. “No one wants a vagina that smells like a stool,” says Ting.

No indeed. But alternatives remained elusive, and brainstorming them kept Ting up at night. “I kept thinking, there’s got to be something better,” he says. “But where were we going to find a large amount of pink, hairless, inner skin that secretes fluid?”