Editor's Note: Jonathan Dudley is the author of Broken Words: The Abuse of Science and Faith in American Politics.

By Jonathan Dudley, Special to CNN

Growing up in the evangelical community, I learned the Bible’s stance on homosexuality is clear-cut. God condemns it, I was taught, and those who disagree just haven’t read their Bibles closely enough.

Having recently graduated from Yale Divinity School, I can say that my childhood community’s approach to gay rights—though well intentioned—is riddled with self-serving double standards.

I don’t doubt that the one New Testament author who wrote on the subject of male-male intercourse thought it a sin. In Romans 1, the only passage in the Bible where a reason is explicitly given for opposing same-sex relations, the Apostle Paul calls them “unnatural.”

Problem is, Paul’s only other moral argument from nature is the following: “Does not nature itself teach you that if a man wears long hair, it is degrading to him, but if a woman has long hair, it is her glory?” (1 Corinthians 11:14-15).

Few Christians would answer that question with a “yes.”

In short, Paul objects to two things as unnatural: one is male-male sex and the other is long hair on men and short hair on women. The community opposed to gay marriage takes one condemnation as timeless and universal and the other as culturally relative.

I also don’t doubt that those who advocate gay marriage are advocating a revision of the Christian tradition.

But the community opposed to gay marriage has itself revised the Christian tradition in a host of ways. For the first 1500 years of Christianity, for example, marriage was deemed morally inferior to celibacy. When a theologian named Jovinian challenged that hierarchy in 390 A.D. — merely by suggesting that marriage and celibacy might be equally worthwhile endeavors — he was deemed a heretic and excommunicated from the church.

How does that sit with “family values” activism today?

Yale New Testament professor Dale B. Martin has noted that today’s "pro-family" activism, despite its pretense to be representing traditional Christian values, would have been considered “heresy” for most of the church’s history.

The community opposed to gay marriage has also departed from the Christian tradition on another issue at the heart of its social agenda: abortion.

Unbeknownst to most lay Christians, the vast majority of Christian theologians and saints throughout history have not believed life begins at conception.

Although he admitted some uncertainty on the matter, the hugely influential 4th and 5th century Christian thinker Saint Augustine wrote, “it could not be said that there was a living soul in [a] body” if it is “not yet endowed with senses.”

Thomas Aquinas, a Catholic saint and a giant of mediaeval theology, argued: “before the body has organs in any way whatever, it cannot be receptive of the soul.”

American evangelicals, meanwhile, widely opposed the idea that life begins at conception until the 1970s, with some even advocating looser abortion laws based on their reading of the Bible before then.

It won’t do to oppose gay marriage because it’s not traditional while advocating other positions that are not traditional.

And then there’s the topic of divorce. Although there is only one uncontested reference to same-sex relations in the New Testament, divorce is condemned throughout, both by Jesus and Paul. To quote Jesus from the Gospel of Mark: “Whoever divorces his wife and marries another commits adultery.”

A possible exception is made only for unfaithfulness.

The community most opposed to gay marriage usually reads these condemnations very leniently. A 2007 issue of Christianity Today, for example, featured a story on its cover about divorce that concluded that Christians should permit divorce for “adultery,” “emotional and physical neglect” and “abandonment and abuse.”

The author emphasizes how impractical it would be to apply a strict interpretation of Jesus on this matter: “It is difficult to believe the Bible can be as impractical as this interpretation implies.”

Indeed it is.

On the other hand, it’s not at all difficult for a community of Christian leaders, who are almost exclusively white, heterosexual men, to advocate interpretations that can be very impractical for a historically oppressed minority to which they do not belong – homosexuals.

Whether the topic is hair length, celibacy, when life begins, or divorce, time and again, the leaders most opposed to gay marriage have demonstrated an incredible willingness to consider nuances and complicating considerations when their own interests are at stake.

Since graduating from seminary, I no longer identify with the evangelical community of my youth. The community gave me many fond memories and sound values but it also taught me to take the very human perspectives of its leaders and attribute them to God.

So let’s stop the charade and be honest.

Opponents of gay marriage aren’t defending the Bible’s values. They’re using the Bible to defend their own.

The opinions expressed in this commentary are solely those of Jonathan Dudley.