As someone who had himself seen firsthand the disastrous results of a so-called “successful” sex reassignment, Sigmundson was inclined to agree with Diamond’s argument that the procedure is wrongheaded. But Sigmundson admits that some of his reservations about joining Diamond in a long-term follow-up on John’s case derived from colleagues who had warned him that Diamond was a “fanatic” with an ax to grind regarding Dr. Money. Further conversations with Diamond, and a reading of his journal articles on sexual development, convinced Sigmundson otherwise: “I came to see that Mickey is a serious researcher and a caring guy who really believed that Money’s theory had caused – and was continuing to cause – great harm to children.” Sigmundson agreed to contact John Thiessen and to ask if he would be willing to cooperate with a follow-up article on his case.

By then, John had been married for two years and wanted nothing more than to put his tortured past behind him. He, at first, refused to participate. But in a later meeting with Dr. Diamond – who flew in from Hawaii, John learned, for the first time, about his fame in the medical literature and how his reportedly successful switch from boy to girl stood as the precedent upon which thousands of sex reassignments had since been performed – and continued to be performed at an estimated rate of five a day globally. “There are people who are going through what you’re going through every day,” John recalls Diamond telling him, “and we’re trying to stop that.”

That was good enough for John. In the spring of 1994, and over the course of the following year, John, his mother and his wife sat for a series of interviews with Diamond and Sigmundson in which they recounted John’s harrowing journey from boy to girl and back again. Using these interviews, plus the detailed clinical records that Sigmundson had kept on Joan’s case, Diamond wrote up the results in a paper in which John’s life was cast as living proof of precisely the opposite of what Money had said it proved 25 years earlier. Diamond wrote that John’s case is evidence that gender identity and sexual orientation are largely inborn, and that while rearing may play a role in helping to shape a person’s sexual identity, nature is by far the stronger of the two forces so much so that even the concerted 12-year efforts of parents, psychologists, psychiatrists, surgeons and hormone specialists could not override it.

The paper, powerful as it was as anecdotal evidence of the neurobiological basis of sexuality, was also a clear warning to physicians about the dangers of sexual reassignment – and not just for children like John, who are born with normal genitals. Diamond argued that the procedure is equally misguided for intersexual newborns, since physicians have no way of knowing in which direction, male or female the infant’s gender identity has differentiated. To stream such children, surgically, into one sex or the other, Diamond argued, is guesswork that consigns a large percent of them to lives as tortured as John Thiessen’s.

It took nearly two years for Diamond and Sigmundson to find a publisher for their paper. “We were turned down by all these journals that said it was too controversial,” says Sigmundson. “The New England Journal, American Psychiatric, American Pediatric.” The article was finally accepted for publication by the American Medical Association’s Archives of Adolescent and Pediatric Medicine in September 1996, with publication set for March 1997. In the intervening seven months, Diamond and Sigmundson felt considerable apprehension as they waited for their bombshell to go off. “We were basically telling all these physicians that they’d been doing the wrong thing for the past 30 years,” Sigmundson says. “We knew we were going to be pissing a lot of people off.”

They were not wrong. One pediatric endocrinologist who has attended medical meetings on the subject since the article’s publication has reported that the discussions cannot even be termed debates: “It’s like screaming fights in these medical conventions at the moment.” Some critics of the article have attempted to dismiss it on the grounds that Diamond is simply using John’s history to embarrass a scientific rival. But Dr. Melvin Grumbach, the eminence grise of pediatric endocrinology, offers a more measured response. “I think Diamond does have a case,” he says. “I think testosterone in utero and an XY-chromosome constitution does do things to you. But the question is: Is it invariable?”

Grumbach points out that sex reassignment is always done as a last resort and only when every other treatment option has been ruled out. And while he admits that sex reassignments are not foolproof, Grumbach insists that they can, and do, work “with good support.” But asked to offer up a “satisfied customer,” Grumbach voices the Catch-22 of every pediatric specialist contacted for this article. “I really lose track of all my patients after young adulthood,” he says.

Astonishingly, in the four decades since the first sex reassignments were performed, no comprehensive, long-term follow-up study of the patients has ever been conducted. Such a study was, finally, launched at the Johns Hopkins medical center in June 1995. Child psychiatrist (and former pediatric urologist) Bill Reiner has been following the lives of 16 reassigned people, focusing on six genetic males who were born without penises, castrated in infancy and raised as girls. Two years into his study, Reiner says that all six are closer to males than to females in attitudes and behavior. Two have spontaneously (without being told of their XY male chromosome status) switched back to being boys. “These are children who did not have penises,” Reiner points out, “who had been reared as girls and yet knew they were boys. They don’t say, ‘I wish I was a boy,’ or ‘I’d really rather be a boy,’ or ‘I think I’m a boy.’ They say, ‘I am a boy.’ ” Reiner (who wrote a supportive editorial to accompany Diamond and Sigmundson’s John/Joan paper) points to the parallel between the children he is studying and Joan Thiessen, who also “knew,” against all evidence to the contrary, that she was a he.