There's still a long way from conservatives allowing gays to get married. But under the same logic, married heterosexual couples are still tempted into sodomy (i.e. oral and anal sex). Society should be able to trust homosexual couples the same way.
The difference, of course, is that the temptation to engage in sodomy must be more compelling for homosexual couples than it is for heterosexual ones, since fewer avenues for physical intimacy are available to the former than to the latter. It would seem, therefore, that those who believe sodomy is a sin should be more tolerant of the act in homosexuals than in heterosexuals, if less trusting of homosexuals to overcome the temptation.
Though I don't pretend to have statistical evidence on the matter, I am willing to bet dollars to donuts that many of the heterosexuals who would not share their pews with unrepentant, practicing homosexuals on Sunday morning enjoyed one form or another of these earthly delights on Saturday night. Perhaps, then, the focus on religious doctrine with respect only to homosexuals is too myopic, and what is needed is a more fundamental reappraisal of religious proscription of what consenting adults may or may not do with their genitals (and other body parts).