His writings include the book, “The Bible and Homosexual Practice” — published in 2001 at a time when several mainline denominations were deadlocked in debates over the role of gay members. In it, he reviews passages throughout the Bible, parsing Hebrew and Greek terms, to argue that “there is clear, strong and credible evidence that the Bible unequivocally defines same-sex intercourse as sin.”

Robert A.J. Gagnon, a biblical scholar who became one of the most outspoken and polarizing opponents of same-sex practice in a generation of debates within his and other Protestant denominations, has resigned from the faculty of the Pittsburgh Theological Seminary.

The seminary is affiliated with the Presbyterian Church (U.S.A.), a denomination that debated sexuality for decades before deciding in 2011 to ordain non-celibate gays and lesbians and in 2015 to authorize same-sex marriages in its churches. Mr. Gagnon, an ordained elder in the denomination, spoke out often against such liberalizing trends.

The seminary and the professor “mutually agreed to end their relationship” effective this past Monday, the East Liberty school said. Mr. Gagnon, 59, was a tenured professor of New Testament and had been on the faculty for 23 years.

“We appreciate the contributions Professor Gagnon has made to our students and the community during his time here and we wish him the best in his future endeavors,” a seminary statement said.

Mr. Gagnon, in a Facebook post, said the decision was mutual and that his departure had nothing to do with any “moral turpitude.”

And while neither the school nor Mr. Gagnon directly linked his departure to his controversial stance on homosexuality, he acknowledged that stance would narrow his prospects for future academic work.

“It is my desire to be forward-looking to the next stage of my career and ministry in the academic world as I seek a new institution in which to teach, research, and minister,” he said. “I think God is calling me to an evangelical institution, if the evangelical world will have me.”

He said it’s “unlikely, given my stances on sexual ethics and Scripture, that any university religion department or mainline denominational seminary would take me.”

The Rev. David Esterline, president of the seminary, declined to elaborate on Mr. Gagnon’s departure but said the school remained committed to diverse viewpoints.

“My vision is of a seminary as broad as the church of Jesus Christ,” he said, including people of “very different understandings of Christian theology.”

Read More