Presidential hopeful Dr. Ben Carson told CNN that prison behavior proves that being gay is a choice in a morning interview. On national television, the award-winning neurosurgeon said: “[A] lot of people who go into prison go into prison straight–and when they come out, they’re gay. So, did something happen while they were in there?”

Carson’s assertion, not surprisingly, isn’t backed up by the numbers. To start with, the level of sexual activity of prison inmates is often overstated. One of the most recent studies on sexual behaviors in U.S. prisons showed that less than 2 percent of respondents had engaged in consensual sex in the last year. (That report is almost 20 years old this year, though, so it’s high time it was revisited)

For some prisoners, sex in prison is, unfortunately, not a matter of choice. Out of a prison population of almost 7 million at the end of 2011, almost 9,000 reported being the victim of a sexual assault–that’s 0.13 percent of all inmates, a thankfully tiny fraction. The number is on the rise, having increased by around 1,000 complaints since 2009. The numbers are far worse for juveniles in custody–10 percent of those surveyed (2,000) said that they had been assaulted in the last 12 months.

It’s not all down to prisoners, either. More Inmates reported being victimized by prison staff than another inmate. Out of the prisoners surveyed, 2 percent said that another prisoner had attacked them but 2.4 percent told administrators that a staff member had sexually assaulted them. Juveniles were three times more likely to be sexually assaulted by prison staff than fellow inmates. As for the question of emerging from prison with a new sexuality, studies have shown that survivors of assaults are more likely to question their sexual identity.