Donating a kidney through your vagina or rectum.

Good news: You can now get a kidney from a vagina.

The kidney doesn't start in the vagina, of course. That's just where it comes out. For several years, doctors have been learning how to do this. It's called "transvaginal nephrectomy" or, more broadly, "natural orifice" surgery. They cut the kidney loose and pull it through an incision in the vaginal wall and out the other end.

Until now, all kidneys removed this way were unhealthy and slated for disposal. But on Friday, doctors at Johns Hopkins University added a new twist. According to Dr. Robert Montgomery, head of Johns Hopkins' transplant division, "The kidney was successfully removed and transplanted into the donor's niece."

That's right: The kidney came out of one person's vagina and was put into another's abdominal cavity.

Why take it out through the vagina? To reduce external damage. If you can get the kidney out through the vagina, then the incision you cut through the abdominal wall only has to be big enough to insert narrow laparoscopic instruments. The smaller the cut, the less pain the patient suffers, and the faster she recovers. "That greatly reduces the inconvenience of donating, and we're hoping that will encourage more people to donate," says Montgomery.

Sounds great. But what about those of us who don't have vaginas?

No problem. Dr. Marc Bessler, a leading natural-orifice surgeon, has mapped an alternative route:

Eventually, Dr. Bessler said, he expects to use the natural-opening technique on men as well as women, with instruments passed down the throat or into the rectum to cut through the wall of the stomach or intestine to reach the gallbladder or other organs. But first, surgeons have to develop techniques to make sure that the cuts in the stomach and intestine can be sealed completely after the operation so that they do not leak into the abdomen, which could cause serious complications. Incisions through the wall of the vagina rarely cause leaks, he said.

I'm sorry … did he say rectum?

I'm afraid he did. And even the vaginal route may be hazardous. The Cleveland Clinic's director of laparoscopic surgery warns, "There is the risk of infection having the kidney passing through a contaminated area and then going to another patient who is immunocompromised."