These days, being known as a gay soldier, network anchor, or even professional athlete is increasingly unremarkable—but just 40 years ago, it not only would have ended your career, it would have branded you as suffering from a “sociopathic personality disorder.” That diagnosis seems barbaric now, but things were even worse before social scientists and others began studying same-sex attraction in the mid-19th century, when it was almost universally considered an act of immoral depravity, and often a crime to boot. Though the conclusions of those pioneering researchers look pretty appalling from the vantage point of 2013, they did lay the first paving stones on the road that has taken us, step by step (with an occasional backward one) to the Supreme Court and the question that may be the capstone of the struggle for equality: Do same-sex couples have the right to marry?

1

Homosexuals aren’t evil, just sick

In the 1860s, several European researchers promoted the notion that practitioners of “perverse” sex should not be seen as criminals, but as victims of mental illness. The Austrian psychiatrist Richard von Krafft-Ebing codified this view in 1886 in his Psychopathia Sexualis, a “medico-forensic study” summarizing psychiatric knowledge about a wide range of “deviant” sexual preferences, from necrophilia to “inversion,” a.k.a. homosexuality. The book became a key source for lawyers and doctors involved in sex-crime court cases, and helped reshape the public’s concept of sexuality. It also influenced a fellow Austrian named Sigmund Freud. In the book’s section, “Homo-Sexual Feeling as an Abnormal Congenital Manifestation,” Krafft-Ebing marveled that “in many instances, the consciousness of the abnormality of the condition is wanting. The majority … are happy in their perverse sexual feeling and impulse, and unhappy only insofar as social and legal barriers stand in the way of the satisfaction of their instinct toward their own sex.” Homosexuality, he added, “is much more frequent than reported cases would lead us to presume.”

—Psychopathia Sexualis, Richard von Krafft-Ebing, first published in 1886

2

They are much more common than we presume

Half a century later, Krafft-Ebing was proved right, at least on one point—homosexuality was a lot more common than generally believed. Alfred Kinsey’s pathbreaking 1948 study, Sexual Behavior in the Human Male, and its 1953 companion volume on women, shocked America with its frank, explicit reporting on what people were doing in their bedrooms, and backed it up with an unprecedented collection of scientific-survey data drawn from more than 10,000 interviews. Kinsey concluded that many people were neither exclusively homosexual nor exclusively heterosexual, but fell somewhere along a continuum between the two, and that their feelings might change through-out life. He classified 10 percent of the men he interviewed as predominantly homosexual—and reported that 37 percent of all males in his sample had had “at least one sexual experience to orgasm.” Kinsey’s findings made headlines around the world, and his books became best sellers.

—Sexual Behavior in the Human Male, Alfred Kinsey et al., 1948

3

Maybe they’re not sick after all

Throughout the first half of the 20th century, study after study found that homosexuals had all kinds of mental and emotional problems. That’s not too surprising, considering that virtually every one of those studies was conducted on gay men or women who were in prison, a mental hospital, or psychiatric treatment. Psychologist Evelyn Hooker was the first to seriously investigate the mental health of homosexual men who seemed to be doing fine. She ran a slew of psychological tests on a group of 30 gay men who were not in therapy and on a comparable group of heterosexual men. She then had three psychiatrists analyze the results, without telling them which subjects were gay and which were straight. The psychiatrists not only declared most men in both groups mentally healthy, but were unable to tell which were which. “I am amazed,” wrote one of the psychiatrists after Hooker revealed the subjects’ sexual orientations. “If you want proof that a homosexual can be normal, this record does it.”

—“The Adjustment of the Male Overt Homosexual,” Journal of Projective Techniques, Evelyn Hooker, 1957

4

Then again, maybe they are

Hooker’s work inspired more such research, but the idea that same-sex attraction was normal remained a radical one. In 1962 prominent psychoanalyst Irving Bieber released the results of the most ambitious survey of homosexual behavior ever conducted up to that time: a nine-year study of 106 gay men and 100 straight men. Bieber resoundingly reaffirmed the notion that homosexuality was a disorder. One of its primary causes, he concluded, was “detached, rejecting fathers” and overbearing mothers who imparted too much femininity to their sons. Bieber’s work won the American Psychiatric Association’s top award. But the tide was slowly turning. In 1973, despite the full-throated opposition of Bieber and many others, the APA’s board of trustees voted to remove homosexuality from the Diagnostic and Statistical Manual of Mental Disorders.

—Homosexuality: A Psychoanalytic Study of Male Homosexuals, Irving Bieber et al., 1962

5

They’re fine, and their kids are too

By now virtually all of the major psychiatric, psychological, sociological, and pediatric professional organizations have officially declared that “being gay is just as healthy as being straight,” as the American Psychological Association puts it. That goes for the children of same-sex parents too. Last year, Cambridge University psychologist Michael Lamb published a survey reviewing more than 100 studies on the subject from the last 30 years. The research, he concluded, shows that “the children and adolescents of same-sex parents are as emotionally healthy, and as educationally and socially successful, as children and adolescents raised by heterosexual parents.” Lamb’s review was cited prominently in several amicus briefs filed with the Supreme Court earlier this year by major mental-health professional associations, urging the justices to rule in favor of same-sex marriage.

—“Mothers, Fathers, Families, and Circumstances: Factors Affecting Children’s Adjustment,” Applied Developmental Science, Michael Lamb, 2012