Rachel Maddow has made the argument that Dr. Robert Spitzer's recent repudiation of “ex-gay” therapy could bolster the case for marriage equality.

Spitzer's highly-criticized 2001 study which was published in the prestigious Archives of Sexual Behavior concluded that “highly motivated” gay men and lesbians could alter their sexuality.

The study was touted by gay rights foes most notably because Spitzer had led the charge in the early 70s to declassify homosexuality as a mental disorder in the Diagnostic and Statistical Manual (DSM) of the American Psychiatric Association and therefore was viewed as unbiased.

Referring to the ongoing lawsuit challenging the constitutionality of California's gay marriage ban, Proposition 8, which took away existing marriage rights, Maddow said: “The case around Prop 8 hinges in part on the question of immutability. Is being gay an immutable characteristic? Can you change it? If you find yourself gay for some reason, do you have to stay that way?”

“One of the arguments the anti-gay rights side makes is that being gay is a choice. So marriage then isn't a question of equal rights. Everybody has an equal right to get married already. If you want to get married and you're gay, you can get married. You just have to stop being gay. Choose to become straight, now you can get married. Presto, change-o, here comes the bride.”

Maddow noted that Spitzer's work was lauded by Proposition 8 supporters during its 2010 trial.

“It was important for the lawyer on the anti-gay side to get it on the record that this prominent study by this prominent expert psychiatrist proved that gay people can change. It is relatively central to their argument that denying gay people access to marriage isn't some kind of second class citizenship for gay people. Gay people have first class citizenship, all they have to do is change into straight people and then they can have all the rights they want.”

Noting that Spitzer has recanted his study and this week even apologized for the possible harm he might have caused, Maddow added: “That argument has just fallen apart.” (Watch the entire segment at HRC.org.)

Spitzer, now 80, told the American Prospect that such therapy “can be quite harmful.”

And in a letter to the editor of the Archives of Sexual Behavior, Spitzer added: “There was no way to judge the credibility of subject reports of change in sexual orientation. 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.”

“I believe I owe the gay community an apology for my study making unproven claims of the efficacy of reparative therapy,” he added. “I also apologize 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 with some 'highly motivated' individuals.”

In a follow up to a previous story, a Maddow staffer posted on her blog an email from the American Psychoanalytical Association: “We emphasize that anti-homosexual bias, just like any other societal prejudice, negatively affects mental health and contributes to feelings of stigma and low self-worth. Reparative therapy is nothing more than quackery fueled by bias.”