Gene Robinson, the gay Episcopal bishop of the diocese of New Hampshire, did not set out to be a lightning rod in the conflict between religion and the drive to legalize gay marriage.

That said, his new book God Believes in Love: Straight Talk About Gay Marriage (Knopf, $24), attacks the anti-gay undertone in many churches.

Robinson has a message for Christians who believe that the Bible condemns gays: It’s time to read your Bible again.

Amicably divorced from the mother of his two grown daughters, he writes about discovering the fullness of love in a gay relationship. He details meeting his husband, Mark Andrew.

“For the first time, I was able to express my love for someone through my body. … I experienced a wholeness and integration between body and spirit I had only dreamed about. I remember thinking, ‘So this is what all the fuss is about! No wonder people like — and hallow — this!’ ”

Robinson deconstructs biblical passages that seem to condemn gay sex. At best, he contends, the invocations against gay sex are products of a time in which all people were assumed to be born heterosexual. Making gayness seem like willful disobedience rather than an inborn orientation was not even considered within the cultural framework of the period.

Robinson also points out that Jesus never addressed homosexuality and in fact spent much of his time with those who were on the outskirts of society.

He also notes that many who consider themselves strict Bible constructionists have moved on from many of the mores set forth in the Bible: We wear clothing of varying fabrics; women don’t cover their heads in church, and women are not considered property; we don’t keep slaves.

Robinson’s book also discusses the prurient interest in gay sexual practices as a source of moral condemnation: “My guess is that gay sex may be every bit as boring as straight sex! Conversely straight sex may be as kinky, naughty and wild as gay sex.”

Public opinion has shifted since the 2003 firestorm that accompanied Robinson’s election as the Episcopal Church’s first gay bishop. “Don’t ask, don’t tell” has been scrapped in the military, and President Barack Obama announced his support of gay marriage in May.

“The thing that’s changing the discussion is that most people know someone gay,” Robinson said in a recent telephone interview. “All the bad things that have been said about gay people don’t seem to be true about the gay people they know. … They know gay couples with children. They know gay couples who have been together for 10, 20, 30, 40 years.”

Robinson argues that “civil unions” do little to invest gay couples with the rights and privileges of marriage, including the right to act as medical and financial guardians for an ailing partner and to be considered a true legal family.

“When negative things are said about gay people … we need to find the courage to say, ‘That doesn’t wash anymore’ and begin to change the atmosphere so that those kinds of negative statements are seen as the toxic things that they are,” Robinson said.

“I believe we are moving to full marriage equality for the nation, and we are now only arguing over timing,” he said. “Court after court has seen this ban as unconstitutional.”