Much like whether Louis Tomlinson of One Direction has a fake baby, male circumcision, or the surgical removal of part or all of the foreskin on the penis, remains a fraught topic. Despite the medical community's wide support of the practice—the CDC officially endorsed circumcision in 2014—men, even those who are not explicitly intactivists, have mixed feelings about the act of cutting off part of their dick.

Studies have shown, however, that circumcision comes with health benefits, including a lower risk of contracting some STIs, a lower risk of contracting UTIs during infancy that could cause kidney damage, and few health risks. In terms of sex and aesthetics, a survey conducted by Queen's University's Sex Lab found that women prefer circumcised penises for vaginal intercourse and fellatio.

Still, men circumcised at birth often lament the fact that they never got to experience life with foreskin. The same survey showed that men "indicated a strong preference toward intact penises for all sexual activities assessed and held more positive beliefs about intact penises." This gender discrepancy makes sense. Women don't want to deal with an extra skin flap that smells kind of weird; on the other hand, it's been considered common knowledge that the foreskin increases penile sensitivity. What guy would want to give that up?

But is a penis sporting a crewcut really less sensitive than one that is safely swaddled in its turtleneck? A 2016 study published in the Journal of Urology, also from Queen's University's Sex Lab, says no. The researchers recruited 62 men aged 18 to 37; roughly half were circumcised and half were not. Led by doctoral student Jennifer Bossio, who has done several studies on the effects of circumcision, researchers found that sensitivity to both heat and pain didn't differ between the two groups.

The idea that the foreskin is more sensitive stems from a 2007 study that measured response to light touch; this study found that "the glans [or the head] of the circumcised penis is less sensitive to fine touch than the glans of the uncircumcised penis." When testing the same metric, Bossio's study also found that the foreskin was indeed more sensitive. Yet she argues that response to heat and pain are more analogous to sexual sensations. "We measured heat detection and heat pain by attaching a thermode to the penis," Bossio told Broadly. "Men would indicate either when they would feel a change in temperature or when it hurt. The nerve fibers in the penis that are activated by temperature and pain are more relevant in sexual functioning—or the feel of a sexy touch—than the light touch that past researchers had done. Even though [the foreskin] is more sensitive to light touch, I suspect that isn't implicated in sexual pleasure. I think that's the take-home message of this study."

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The most extreme of anti-circumcision activists often like to compare the routine surgery to the obviously horrific practice of female genital mutilation (FGM). But that circumcision actively harms the physical aspects of male sexual function is not backed by science, Bossio said. "With FGM, oftentimes the clitoris is removed, which would be the equivalent of removing the entire penis." She said the surgery could be more accurately understood as a cosmetic modification like labiaplasty. "All of these self-reports from men who say, 'Circumcision ruined my penis' are not necessarily supported by what we are finding," Bossio said. "It was my hope that this study would calm people's fears [about circumcision]. We really found no evidence that a circumcised penis differs from an uncircumcised penis."

Bossio notes that a forthcoming study from the Sex Lab, in which the same group of men were shown porn, found that the men's sexual response—both their sexual arousal and their subjective experience of sexual arousal—also didn't differ between those who were circumcised and those who weren't.