I live in Canada where the courts have ruled that gay marriages are legal. Many churches are willing to perform gay marriages although probably a majority do not.
Since the 1920's Canada has become progressively more liberal in its approach to human sexuality. In the 1960's we made divorce no fault, legalized birth control, decriminalized homosexuality and banned discrimination against homosexuals. Our government has admitted that church employees acting as agents of government physically and sexually abused Indian Students who were forced into residential schools, "illegitimate" children who were warehoused in mental hospitals and orphanages. Compensation is now being paid to these individuals who, as helpless children had their lives destroyed by abusive clergy.
Today the same conservative churches who committed these abuses now demand that marriage is the sacred basis of the family and should be reserved exclusively for heterosexual couples because homosexual couples cannot produce children. This is a ridiculous argument. does it mean that infertile couples can't marry? should couples using contraceptives have their sacred marriage privilege suspended? The notion that opening marriage to gays will lead to inter-species marriage or polygamy is equally fallacious.
Science has taught us that human sexuality is not based on 2 polarities but on a whole spectrum of preferences that are programmed into us at birth. It is about time that the law recognized that. It is not certain that churches ever will because sex has been exploited by churches as a source of fear and guilt to keep their congregants in line and submissive.