Causes of homosexuality (probably; see for discussion).
The slogan "Homosexuality is a choice" asserts that choosing to engage in or homosexual activity is a matter of conscious choice. Religious authorities regarding homosexuality as sinful believe that all persons ought to refrain from homosexual acts. People having a homosexual identitity or orientation but who desire to comply with this edict, sometimes make the decision not to engage in homosexual sexual activity is based on a religious belief that the "choice" to be celibate is more moral than the "choice" to have sex.
Also, the slogan can indicate a broader or more encompassing view that "being a homosexual" or not is a matter of individual choice.
A related question is whether abstaining from homosexual activity makes the person not "homosexual". Whether an abstinent heterosexual is not a heterosexual is not usually addressed by those expressing this view, perhaps because several major religions require celibacy from their religious leaders, it's sometimes considered to be good to be a virgin on your wedding day or because children are usually abstinent.
Opponents generally retort that "Homosexuality is not a choice." See "No one chooses to be gay". They also sometimes retort "Mind your own business", "" and "".
Catherine Harris of Boston University, writes:
She adds: "Many gays and lesbians have embraced the position that homosexuality is not a choice because they feel that less discrimination and prejudice will be forthcoming for something that is genetic, biological, or otherwise not a choice." [1]
Vera Whisman says that many more women than men give accounts of having chosen their sexuality and argues that "it is not scientific research but political struggle that will protect gay men, lesbians, and bi-sexuals." Homosexuals can counter prejudice by asserting that, "Homosexuality is a perfectly reasonable choice to make." [2]