A trio of Iowa-based religious scholars penned an op-ed in a local paper this week, reminding readers that despite popular opinion, the Bible does not simply define marriage as between one man and one woman.

The joint editorial was written by Hector Avalos, Robert R. Cargill and Kenneth Atkinson and published in the Des Moines Register on Sunday. The men teach at Iowa State University, University of Iowa and University of Northern Iowa, respectively.

“The debate about marriage equality often centers, however discretely, on an appeal to the Bible,” the authors wrote. “Unfortunately, such appeals often reflect a lack of biblical literacy on the part of those who use that complex collection of texts as an authority to enact modern social policy.”

The Bible’s definition of marriage can be confusing and contradictory, noted the scholars. They stated in their column that a primary example of this is the religious book’s stance on polygamy, a practice that was embraced by prominent biblical figures Abraham and David. Furthermore, Avalos, Cargill and Atkinson point out that various Bible passages mention not only traditional monogamy, but also self-induced castration and celibacy, as well as the practice of wedding rape victims to their rapists.

In an interview with The Huffington Post, Iowa University Professor Robert R. Cargill said the column was the brainchild of his colleague Hector Avalos, who suggested local scholars put together an “educated response” to the often-touted claim that the Bible defines marriage as solely between one man and one woman. “[T]hat’s not the only thing the Bible says,” Cargill told HuffPost.

He explained that it is obvious to scholars (and some religious leaders) that the Bible endorses a wide range of relationships. But he noted, however, that professors are “terrified” of the potential backlash that might result from opening a dialogue about these relationships. Cargill also noted that the initial response to the Register column has included its fair share of vitriol.

Ultimately, said Cargill, a Biblical “argument against same-sex marriage is wholly unsustainable. We all know this, but very few scholars are talking about it, because they don’t want to take the heat.”