What to say? The issue of gay marriage was rocking national politics yet again. The California State Legislature was debating a bill to ban the therapy outright as being dangerous. A magazine writer who had been through the therapy as a teenager recently visited his house, to explain how miserably disorienting the experience was. 
 
 And he would later learn that a World Health Organization report, released on Thursday, calls the therapy “a serious threat to the health and well-being — even the lives — of affected people.” 
 
 Dr. Spitzer’s fingers jerked over the keys, unreliably, as if choking on the words. And then it was done: a short letter to be published this month, in the same journal where the original study appeared. 
 
 “I believe,” it concludes, “I owe the gay community an apology.” 
 
 Disturber of the Peace 
 
 The idea to study reparative therapy at all was pure Spitzer, say those who know him, an effort to stick a finger in the eye of an orthodoxy that he himself had helped establish. 
 
 In the late 1990s as today, the psychiatric establishment considered the therapy to be a nonstarter. Few therapists thought of homosexuality as a disorder. 
 
 It was not always so. Up into the 1970s, the field’s diagnostic manual classified homosexuality as an illness, calling it a “ sociopathic personality disturbance.” Many therapists offered treatment, including Freudian analysts who dominated the field at the time. 
 
 Advocates for gay people objected furiously, and in 1970, one year after the landmark Stonewall protests to stop police raids at a New York bar, a team of gay rights protesters heckled a meeting of behavioral therapists in New York to discuss the topic. The meeting broke up, but not before a young Columbia University professor sat down with the protesters to hear their case. 
 
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 “I’ve always been drawn to controversy, and what I was hearing made sense,” said Dr. Spitzer, in an interview at his Princeton home last week. “And I began to think, well, if it is a mental disorder, then what makes it one?” 
 
 He compared homosexuality with other conditions defined as disorders, like depression and alcohol dependence , and saw immediately that the latter caused marked distress or impairment, while homosexuality often did not. 
 
 He also saw an opportunity to do something about it. Dr. Spitzer was then a junior member of on an American Psychiatric Association committee helping to rewrite the field’s diagnostic manual, and he promptly organized a symposium to discuss the place of homosexuality. 
 
 That kicked off a series of bitter debates, pitting Dr. Spitzer against a pair of influential senior psychiatrists who would not budge. In the end, the psychiatric association in 1973 sided with Dr. Spitzer, deciding to drop homosexuality from its manual and replace it with his alternative, “sexual orientation disturbance,” to identify people whose sexual orientation, gay or straight, caused them distress. 
 
 The arcane language notwithstanding, homosexuality was no longer a “disorder.” Dr. Spitzer achieved a civil rights breakthrough in record time. 
 
 “I wouldn’t say that Robert Spitzer became a household name among the broader gay movement, but the declassification of homosexuality was widely celebrated as a victory,” said Ronald Bayer of the Center for the History and Ethics of Public Health at Columbia. “ ‘Sick No More’ was a headline in some gay newspapers.” 
 
 Partly as a result, Dr. Spitzer took charge of the task of updating the diagnostic manual. Together with a colleague, Dr. Janet Williams, now his wife, he set to work. To an extent that is still not widely appreciated, his thinking about this one issue — homosexuality — drove a broader reconsideration of what mental illness is, of where to draw the line between normal and not. 
 
 The new manual, a 567-page doorstop released in 1980, became an unlikely best seller, here and abroad. It instantly set the standard for future psychiatry manuals, and elevated its principal architect, then nearing 50, to the pinnacle of his field. 
 
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 He was the keeper of the book, part headmaster, part ambassador, and part ornery cleric, growling over the phone at scientists, journalists, or policy makers he thought were out of order. He took to the role as if born to it, colleagues say, helping to bring order to a historically chaotic corner of science. 
 
 But power was its own kind of confinement. Dr. Spitzer could still disturb the peace, all right, but no longer from the flanks, as a rebel. Now he was the establishment. And in the late 1990s, friends say, he remained restless as ever, eager to challenge common assumptions. 
 
 That’s when he ran into another group of protesters, at the psychiatric association’s annual meeting in 1999: self-described ex-gays. Like the homosexual protesters in 1973, they too were outraged that psychiatry was denying their experience — and any therapy that might help. 
 
 Reparative Therapy 
 
 Reparative therapy, sometimes called “sexual reorientation” or “conversion” therapy, is rooted in Freud’s idea that people are born bisexual and can move along a continuum from one end to the other. Some therapists never let go of the theory, and one of Dr. Spitzer’s main rivals in the 1973 debate, Dr. Charles W. Socarides, founded an organization called the National Association for Research and Therapy of Homosexuality, or Narth, in Southern California , to promote it. 
 
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 By 1998, Narth had formed alliances with socially conservative advocacy groups and together they began an aggressive campaign, taking out full-page ads in major newspaper trumpeting success stories. 
 
 “People with a shared worldview basically came together and created their own set of experts to offer alternative policy views,” said Dr. Jack Drescher, a psychiatrist in New York and co-editor of “Ex-Gay Research: Analyzing the Spitzer Study and Its Relation to Science, Religion, Politics, and Culture.” 
 
 To Dr. Spitzer, the scientific question was at least worth asking: What was the effect of the therapy, if any? Previous studies had been biased and inconclusive. “People at the time did say to me, ‘Bob, you’re messing with your career, don’t do it,’ ” Dr. Spitzer said. “But I just didn’t feel vulnerable.” 
 
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 He recruited 200 men and women, from the centers that were performing the therapy, including Exodus International, based in Florida , and Narth. He interviewed each in depth over the phone, asking about their sexual urges, feelings and behaviors before and after having the therapy, rating the answers on a scale. 
 
 He then compared the scores on this questionnaire, before and after therapy. “The majority of participants gave reports of change from a predominantly or exclusively homosexual orientation before therapy to a predominantly or exclusively heterosexual orientation in the past year,” his paper concluded. 
 
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 The study — presented at a psychiatry meeting in 2001, before publication — immediately created a sensation, and ex-gay groups seized on it as solid evidence for their case. This was Dr. Spitzer, after all, the man who single-handedly removed homosexuality from the manual of mental disorders. No one could accuse him of bias. 
 
 But gay leaders accused him of betrayal, and they had their reasons. 
 
 The study had serious problems. It was based on what people remembered feeling years before — an often fuzzy record. It included some ex-gay advocates, who were politically active. And it did not test any particular therapy; only half of the participants engaged with a therapist at all, while the others worked with pastoral counselors, or in independent Bible study. 
 
 Several colleagues tried to stop the study in its tracks, and urged him not to publish it, Dr. Spitzer said. 
 
 Yet, heavily invested after all the work, he turned to a friend and former collaborator, Dr. Kenneth J. Zucker, psychologist in chief at the Center for Addiction and Mental Health in Toronto and editor of the Archives of Sexual Behavior, another influential journal. 
 
 “I knew Bob and the quality of his work, and I agreed to publish it,” Dr. Zucker said in an interview last week. The paper did not go through the usual peer-review process, in which unnamed experts critique a manuscript before publication. “But I told him I would do it only if I also published commentaries” of response from other scientists to accompany the study, Dr. Zucker said. 
 
 Those commentaries, with a few exceptions, were merciless. One cited the Nuremberg Code of ethics to denounce the study as not only flawed but morally wrong. “We fear the repercussions of this study, including an increase in suffering, prejudice, and discrimination,” concluded a group of 15 researchers at the New York State Psychiatric Institute, where Dr. Spitzer was affiliated. 
 
 Dr. Spitzer in no way implied in the study that being gay was a choice, or that it was possible for anyone who wanted to change to do so in therapy. But that didn’t stop socially conservative groups from citing the paper in support of just those points, according to Wayne Besen, executive director of Truth Wins Out, a nonprofit group that fights antigay bias. 
 
 On one occasion, a politician in Finland held up the study in Parliament to argue against civil unions, according to Dr. Drescher. 
 
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 “It needs to be said that when this study was misused for political purposes to say that gays should be cured — as it was, many times — Bob responded immediately, to correct misperceptions,” said Dr. Drescher, who is gay. 
 
 But Dr. Spitzer could not control how his study was interpreted by everyone, and he could not erase the biggest scientific flaw of them all, roundly attacked in many of the commentaries: Simply asking people whether they have changed is no evidence at all of real change. People lie, to themselves and others. They continually change their stories, to suit their needs and moods. 
 
 By almost any measure, in short, the study failed the test of scientific rigor that Dr. Spitzer himself was so instrumental in enforcing for so many years. 
 
 “As I read these commentaries, I knew this was a problem, a big problem, and one I couldn’t answer,” Dr. Spitzer said. “How do you know someone has really changed?” 
 
 Letting Go 
 
 It took 11 years for him to admit it publicly. 
 
 At first he clung to the idea that the study was exploratory, an attempt to prompt scientists to think twice about dismissing the therapy outright. Then he took refuge in the position that the study was focused less on the effectiveness of the therapy and more on how people engaging in it described changes in sexual orientation. 
 
 “Not a very interesting question,” he said. “But for a long time I thought maybe I wouldn’t have to face the bigger problem, about measuring change.” 
 
 After retiring in 2003, he remained active on many fronts, but the reparative study remained a staple of the culture wars and a personal regret that wouldn’t leave him be. The Parkinson’s symptoms have worsened in the past year, exhausting him mentally as well as physically, making it still harder to fight back pangs of remorse. 
 
 And one day in March, Dr. Spitzer entertained a visitor. Gabriel Arana, a journalist at the magazine The American Prospect, interviewed Dr. Spitzer about the reparative therapy study. This was not just any interview; Mr. Arana went through reparative therapy himself as a teenager, and his therapist had recruited the young man for Dr. Spitzer’s study (Mr. Arana did not participate). 
 
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 “I asked him about all his critics, and he just came out and said, ‘I think they’re largely correct,’ ” said Mr. Arana, who wrote about his own experience last month. Mr. Arana said that reparative therapy ultimately delayed his self-acceptance as a gay man and induced thoughts of suicide. “But at the time I was recruited for the Spitzer study, I was referred as a success story. I would have said I was making progress.” 
 
 That did it. The study that seemed at the time a mere footnote to a large life was growing into a chapter. And it needed a proper ending — a strong correction, directly from its author, not a journalist or colleague. 
 
 A draft of the letter has already leaked online and has been reported. 
 
 “You know, it’s the only regret I have; the only professional one,” Dr. Spitzer said of the study, near the end of a long interview. “And I think, in the history of psychiatry, I don’t know that I’ve ever seen a scientist write a letter saying that the data were all there but were totally misinterpreted. Who admitted that and who apologized to his readers.” 
 
 He looked away and back again, his big eyes blurring with emotion. “That’s something, don’t you think?” ||||| One of the most influential figures in modern psychiatry has apologised to America's gays for a scientific study which supported attempts to "cure" people of their homosexuality. 
 
 The survey, published in 2001, looked at "reparative therapy" and was hailed by religious and social conservatives in America as proof that gay people could successfully become straight if they were motivated to do so. 
 
 But Dr Robert Spitzer has now apologised in the same academic journal that published his original study, calling it "fatally flawed". "I believe I owe the gay community an apology," his letter said. "I also apologise to any gay person who wasted time and energy undergoing some form of reparative therapy because they believed that I had proven that reparative therapy works." 
 
 Spitzer's letter, which was leaked online before its publication in the Archives of Sexual Behaviour, is sure to cause delight among gay civil rights groups and stir up anger among social conservatives, who have used the study to combat the acceptance of homosexuality as a normal part of human society. 
 
 Reparative therapy is popular among Christian conservative groups, which run clinics and therapy sessions at which people try to become heterosexual through counselling. Gay rights activists condemn such practices as motivated by religious faith, not science, and call them "pray away the gay" groups. 
 
 Spitzer's study looked at the experiences of 200 people undertaking the therapy, including subjects that had been provided by religious groups. He then asked each person the same set of questions, analysing their responses to the therapy and their feelings and sexual urges afterwards. He concluded that many of them reported feelings of changes in their sexual desires from homosexual to heterosexual. 
 
 Spitzer's stance was notorious, because in 1973 he had been instrumental in getting the American Psychiatric Association to stop classifying homosexuality as a mental disorder in its diagnostic manual: a move seen at the time as a major victory for gay rights. 
 
 His 2001 study caused a huge stir because many people felt that it was not rigorous enough for publication. The central criticism was that Spitzer had not paid enough attention to the fact that subjects might lie about their feelings or be engaged in self-deception. 
 
 For more than a decade Spitzer shrugged off the attacks and stood by his work, but he has now admitted that his critics were right. "I offered several (unconvincing) reasons why it was reasonable to assume that the subject's reports of change were credible and not self-deception or outright lying. But the simple fact is that there was no way to determine if the subject's accounts of change were valid," Spitzer wrote. 
 
 In an interview with the New York Times last week, Spitzer, who is 79 and suffers from Parkinson's disease, described how he had written his letter of recantation in the middle of the night after agonising over the study's impact. 
 
 He had also recently been visited by a gay magazine journalist, Gabriel Arana, who had described to him his own experience going through reparation therapy and how damaging it had been and how it had led to thoughts of suicide. "It's the only regret I have; the only professional one," Spitzer told the New York Times, which described him as being almost in tears as he talked about his decision to admit he was wrong. 
 
 "In the history of psychiatry I don't know that I've ever seen a scientist write a letter saying that the data were all there but were totally misinterpreted. Who admitted that and who apologised to his readers. That's something, don't you think?" Spitzer told the newspaper. 
 
 Gay rights group Truth Wins Out published the full text of the letter on its website and hailed the moment as a major step forward. "Spitzer's apology to the victims of 'pray away the gay' therapy … marks a watershed moment in the fight against the 'ex-gay' myth," the group said.
– A psychiatrist who revolutionized how people view homosexuality has given a tearful apology for a study that supported the notion of a "gay cure." The New York Times looks at how Dr. Robert Spitzer conducted his study, withstood years of merciless criticism, and, suffering from Parkinson’s, finally wrote his mea culpa. "You know, it’s the only regret I have; the only professional one,” he said. In the 1970s, Spitzer overturned the notion that homosexuality was a mental disorder, but years later risked his career by concluding that "gay cure" therapy could make gay men straight. Critics lambasted his study, noting he had based it on interviews, not solid evidence. Anti-gay advocates seized the moment, using his study as proof that homosexuality could be cured. Now, one gay rights group is hailing Spitzer's apology, the Guardian reports, saying it "marks a watershed moment in the fight against the 'ex-gay' myth."