Conservative Christians often bristle at the charge that they are bigots because of their views about homosexuality and their exclusion of gay men and lesbians from church institutions. They are sometimes right to be upset; such charges are at times unfairly made. An important question that should precede such accusations too often goes unanswered: Just when does religious belief become bigotry or unfair bias?

In examining allegations of housing discrimination, a simple test proves helpful. If potential tenants complain they are excluded from a specific housing unit because of race or religion, authorities send out two sets of people to look at the same unit. One couple will be from the same group as the complaining potential tenants; the other will look like the landlord. Both will present similar credentials. If the landlord rejects both, it counters the charge of bias — the decision probably was based on some other ground common to all three couples. If the landlord rejects the couple that is different (the black couple or the Muslims) and then offers to lease the apartment to the couple that look like him, it tends to confirm unfair bias.

It’s fair to present a similar test to Christian groups who say their actions of exclusion of gay men and lesbians come from their Christian belief. The key question through which to evaluate the integrity of such a claim is this: Do scriptural rules apply evenly to people who are like them and to those who are different? If so, that religious belief seems to have integrity. If not, it seems to reflect a bias against those who are different.

Fortunately, the Gospels present a wonderful test case. Christian conservatives, with some justification, often rest their exclusion of gay men and lesbians on Jesus’ words in Matthew 19. There, Jesus responds to Pharisees who test him by asking if it is “lawful for a man to divorce his wife for any cause.” Jesus responds that God made people male and female, and “for this reason a man shall leave his father and mother and be joined to his wife.” He concludes: “And I say to you, whoever divorces his wife, except for unchastity, and marries another commits adultery.”

This passage does two things. First, the language arguably seems to favor male/female couples as God’s intended family structure. Second, and much more directly, it condemns remarriage after divorce (with an exception for infidelity). Thus, two types of couples are condemned: Straight couples who remarry after a divorce, and same-sex couples. One of these, the straight people who remarry after divorce, appears to be much like the people found in conservative churches. The other type — the same-sex couples — are different. If both types are treated the same (either accepted or rejected), then it would seem that the church or organization is acting without bias — it is simply following a fair reading of Matthew 19.

On the other hand, if they reject the couple that is not like them (the same-sex couple) but welcome the remarried couple without question, it would seem these actions come from a bias against gay men and lesbians rather than a straightforward application of biblical directives regarding sexuality.

Too many institutions fail this test. Pastors rail against gay marriage, looking right past remarried parishioners who more squarely fail the test of Matthew 19.

After the riots in Detroit, my family moved to the all-white suburb of Grosse Pointe Shores. It was a common sight there to see black motorists pulled over for traveling a few miles over the speed limit. White motorists were not held to the same standard. It was bigotry and bias, but the people who lived in Grosse Pointe didn’t complain. After all, it wasn’t us by the side of the road, our heads bowed, excluded and humiliated. It was someone different.

Mark Osler, formerly of the Baylor Law School faculty, is a professor of law at the University of St. Thomas Law School in Minnesota.