The Internet Archive (Wayback Machine) showed its last snapshot of that APA page  on June 26, 2015 – the date of the Obergefell “same-sex marriage” ruling. Coincidence? Hard to believe, because the Supreme Court needed to say homosexuality is immutable in order to declare “same-sex marriage” a fundamental right.
The American Psychiatric Association (APA) long ago (1973) caved to the radical homosexual demands to remove homosexuality from the list of mental disorders. (The American Psychological Association did so in 1975.) The APA has supported “same-sex marriage” since 2005, to support “the stability of [same-sex couples’] relationships and their mental health.” Even so, the group admitted that science does not back up the claim that homosexuals are “born that way.”
Apparently, since that admission would undermine the Supreme Court’s Obergefell ruling, their earlier statement on the causes of homosexuality has been taken down, even as they posted a celebration of the ruling.
The idea that homosexual “orientation” is an inborn, immutable characteristic was key to demands for “gay rights” as fundamental human rights. The ploy was to equate homosexuality with inborn traits such as race, ethnicity, or biological sex (male or female), already protected in U.S. law, thus earning the LGBT community protection as a special class.
The US Supreme Court Obergefell ruling accepted the “born that way” myth, without noting any scientific evidence. Justice Anthony Kennedy’s majority opinion simply declared homosexuality and “sexual orientation” to be “immutable” in two throw-away lines:
The Constitution promises liberty to all within its reach, a liberty that includes certain specific rights that allow persons, within a lawful realm, to define and express their identity. The petitioners in these cases seek to find that liberty by marrying someone of the same sex and having their marriages deemed lawful on the same terms and conditions as marriages between persons of the opposite sex.... And their immutable nature dictates that same-sex marriage is their only real path to this profound commitment. …
For much of the 20th century, moreover, homosexuality was treated as an illness. When the American Psychiatric Association published the first Diagnostic and Statistical Manual of Mental Disorders in 1952, homosexuality was classified as a mental disorder, a position adhered to until 1973. … Only in more recent years have psychiatrists and others recognized that sexual orientation is both a normal expression of human sexuality and immutable.
There’s a big problem with the Court’s “immutable” claim: The homosexual-affirming American Psychiatric Association (as recently as June 2015) stated that “sexual orientation” is not innate, but is fluid, developing or changing over time. People are not “born that way” (as “gay,” lesbian, or bisexual); and there is no science to back up the belief that they are. Here is the APA statement:"Some people believe that sexual orientation is innate and fixed; however, sexual orientation develops across a person’s lifetime. Individuals maybe become aware at different points in their lives that they are heterosexual, gay, lesbian, or bisexual. … No one knows what causes heterosexuality, homosexuality, or bisexuality. … Currently there is a renewed interest in searching for biological etiologies for homosexuality. However, to date there are no replicated scientific studies supporting any specific biological etiology for homosexuality." 
The APA also admitted that that the concept of “sexual orientation” is a recent invention: “Sexual orientation is a relatively new concept. In fact, although same sex behavior has always existed, the idea of a homosexual identity or a homosexual person is only about 100 years old.”
There's another reason the APA may be in the process of revising their statements on sexual orientation. Their admission that there is no replicated scientific support for the claim of innate and immutable "sexual orientation" undermines ongoing efforts to pass bans on counseling related to homosexuality ("sexual orientation change therapy").
Since 2008 the other mental health professional group, the American Psychological Association, also has admitted that there is no scientific evidence that homosexuals are “born that way,” while emphasizing that “lesbian, gay, and bisexual orientations are not disorders.” The psychologists’ organization claims that “orientations” (“heterosexual, bisexual, gay or lesbian”) have not been shown to be a natural biological state, but develop in still mysterious ways. “Sexual orientation” can be fluid, they say, and it is up to the individual to self-label:
Further, the psychologists’ group still posts this statement, “Sexual Orientation & Homosexuality: Answers to Your Questions For a Better Understanding”:
"There is no consensus among scientists about the exact reasons that an individual develops a heterosexual, bisexual, gay or lesbian orientation. Although much research has examined the possible genetic, hormonal, developmental, social and cultural influences on sexual orientation, no findings have emerged that permit scientists to conclude that sexual orientation is determined by any particular factor or factors. Many think that nature and nurture both play complex roles; most people experience little or no sense of choice about their sexual orientation."
The American Psychological Association is behind the times and needs to get its website in line with the Court ruling!Will they soon follow the lead of the APA and send their problematic statements down the memory hole?
Pamphlet recently removed from American Psychiatric
Association website (but now available here):
 Another URL which led to this same page, http://www.psychiatry.org/mental-health/people/lgbt-sexual-orientation, was last captured by Internet Archive on June 28, 2015. Both pages were posted starting in 2012. A brochure with the same information (“Let’s Talk Facts about Sexual Orientation”) has also been removed; available at Internet Archive by clicking here, or on image on right-hand column here.
 Note the Court’s claim that individuals are free “to define … their identity.” But why is this identity in need of defining by the person if it is inborn?
 Note that the APA denies in the above statement that people are naturally born heterosexual, and classifies heterosexuality as an “orientation” with unknown causes which develops over time. Another document (from 2013) taken down by the APA says, “The American Psychiatric Association believes that the causes of sexual orientation (whether homosexual or heterosexual) are not known at this time and likely are multifactorial including biological and behavioral roots which may vary between different individuals and may even vary over time.” (“Position Statement on Issues Related to Homosexuality,” December 2013; dead URL www.psychiatry.org/File%2520Library/Learn/Archives/Position-2013-Homosexuality.pdf; cached at Google.) An APA Fact Sheet from 2014 has also been removed: “Mental Health Disparities: Lesbian/Gay/Bisexual/Transgender” can be accessed by searching the title on Google and clicking on the cached arrow. Are their 2014 facts no longer facts?