From Dirk Diggler's 13-inch schlong and Russian mystic Rasputin's disembodied 11-inch penis displayed at the Russian Museum of Erotica, to the viral micro-penis phenomenon, people are endlessly fascinated by who is and isn't 'well hung.'

While pop culture dictates that large penises are more desirable than small or average-sized ones, what actually contributes to penis length isn't always clear.

The Hard Facts

The Kinsey Institute identified the average erect penis length at 5 to 6-and-a-half inches — a far cry from figures mentioned in pop cultural penile one-upmanship.

BJU Journal - wiley.com

Though urban legends have purported that foot and hand size correlate to penis length, a 2015 study published in the journal BJU International found that this isn't the case.

A 2011 study published in the Asian Journal of Andrology found that index finger length may factor into the penile equation, and that men with a smaller ratio of index finger to ring finger length had longer endowments below the belt, but other medical research, including the BJU study, hasn't found this link to be significant.

Of all the factors and physical traits the BJU study identified, the one most related to penis size was height. Though the 'taller guy-bigger dick' correlation was consistent, it was still relatively weak, according to the study's authors, so swiping right for tall dudes doesn't guarantee you a bigger package.

The Evolution of Big Dicks

While we may not be able to determine the penis size of strangers by shaking hands or eyeballing their shoe-size, human beings have evolved to have larger penises than other primates.

"Before clothing, the nonretractable human penis would have been conspicuous to potential mates," researcher Brian Mautz reported. "Female mate choice could have driven the evolution of larger penises in humans."

In 2012, Mautz studied how penis size influences sexual selection. "Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans," he wrote. But he also concluded that other factors contributed more to perceived attractiveness than endowment, and that tall men and men with broad shoulders were universally considered better looking.

Do Bigger Penises Mean Better Sex?

Some women prefer larger penises because they make it easier to achieve vaginal orgasms during sex.

In January 2016, Men's Health reported that Scottish researchers studied more than 300 women, and found that close to half experienced vaginal orgasms in a month. A third of these lucky ladies subscribed to 'the bigger the better' school of thought, but they also reported more total orgasms than other women included in the study.

“By filling the vagina, a longer penis would aid and abet the displacement of semen left by other males as a means of maximizing the likelihood of paternity,” Gordon Gallup, Ph.D., an evolutionary psychologist at the University of Albany, and one of the study's authors, said.

Width also factors into the equation. A University of Texas study identified that 90 percent of women valued penis thickness over length in their sexual partners. But don't get out your measuring tape too soon — 85 percent of women surveyed by California State University said they were satisfied with the size of their partners' genitals.

Penis size can factor differently into the sexual experiences of gay men. “There's a comparison that happens inherently,” Will, a 26-year-old linguist, told ATTN:. “If the other guy is bigger, it's like, does he think mine is small? And if it's smaller you feel a weird, stupid sense of superiority.”

He said that while the urge to compare was inevitable, he personally didn’t care about size. “As gay men we generally like playing with dicks, no matter what the size.” He added, “On another note, guys who brag about their dick size are fucking annoying, gay or straight. You just got lucky, shut up about it. And size queens are annoying too. You really have a cutoff for the dick size you'll play with? That totally discounts trans men, but a lot of gay guys do that anyway.”

Additionally, research has shown that women care more about penis size in terms of one-night stands than long term partners, and that their ideal length was 6.4 inches, still within the average range. Nothing to worry about. Your penis is fine just the way it is.

This story, first published on Feb. 10, was updated on March 3 due to a request from a source to keep his last name anonymous.