In an interview with CNN's Chris Cuomo on Wednesday morning, likely 2016 presidential candidate Ben Carson, a neurosurgeon, stated his belief that homosexuality is a choice. His evidence for the claim? "A lot of people who go into prison, [they] go into prison straight and when they come out, they're gay."

Carson's comments were a response to Cuomo's questions regarding his opinion on same-sex marriage, which Carson opposes. When Cuomo pointed out that states had voted to uphold racially biased laws, just as they'd voted to ban same-sex marriage, Carson differentiated between race and sexual orientation as rationales for overturning those decisions.

"The fundamental assumption of the analogy he's using is insane," said Helen Eigenberg, professor of criminal justice at the University of Tennessee, who has been studying sexuality and incarceration for about 25 years. "I don't know of any research that substantiates the [claim] that men go to prison and come out gay. There's no data to support that claim," she said.

"In the 1950s or '60s, there was a concept of situational homosexuality that talked about men going to prison and 'became gay' because of the lack of women," Eigenberg said. "But that concept is not accepted among experts in the field any longer." Public sexual identity can change, of course; people who are gay aren't always open about it. "Whether some men believe that they might have come out of prison expressing a different sexual orientation doesn't mean that prison made them gay," she continued.

"Who you fall in love with is never a matter of choice," June Reinisch said when reached by phone. A former professor of psychology at Columbia and Rutgers, she ran the famous Kinsey Institute at Indiana University for 11 years. "Behavior is one thing and the heart is another thing. You ask people, 'Did you choose to be heterosexual?' and they say, 'No, it's who I fell in love with.' It's not a matter of choice. You can choose behavior."

A recent poll shows that more than half of Americans disagree with Carson and support the ability of same-sex couples to get married.