Days like this make me love my job. I spent the last hour reading an article about the human penis: “Secrets of the Phallus: Why Is the Penis Shaped Like That?” Written by Jesse Bering at Scientific American, the piece explores the research of evolutionary psychologist Gordon Gallup at SUNY Albany, who has spent his life wondering why in the hell the human penis is so funny looking. After the jump, eight impressive and interesting tidbits from his research, including how I might someday bear the child of Ryan Gosling.
“The erect human penis is especially large compared to that of other primates, measuring on average between five and six inches in length and averaging about five inches in circumference.” Our closest living relative, the chimp, is nowhere near as large, even at its most riled up.
Only the human phallus has such a distinctive mushroom cap-type head/glans. “Chimpanzees, gorillas and orangutans have a much less extravagant phallic design, more or less all shaft.” Another unique attribute? The corneal ridge, where the head meets the shaft — it plays a significant role in Gallup’s research.
During sex, the penis swells inside the vagina and “occupies the vaginal tract, and with full penetration can even reach the woman’s cervix and lift her uterus.” Further evidence that guys with smaller dicks were given the short end of the biological stick.
Even though humans are relatively monogamous (especially when compared to other species), we weren’t always so loyal, which is why the human penis adapted to deal with competing sperm from other mates. Gallup’s “semen displacement theory” suggests that the human penis is meant to deposit sperm as deep in the vagina as possible, outshooting sperm from other sexual partners, biology’s way of “ensuring” paternity.
Speaking of ejaculate, it can shoot a whopping two feet!
Another way the human penis outsmarts the competition? By getting rid of the competition’s sperm. According to Gallup’s theory, human male “penises were sculpted in such a way that the organ would effectively displace the semen of competitors from their partner’s vagina, a well-synchronized effect facilitated by the ‘upsuck’ of thrusting during intercourse.” Basically, the frenetic thrusting not only encourages the penis to ejaculate, but it also flushes out the sperm left behind by prior partners.
Gallup wanted to study the biological and the behavioral, so he polled college students about their “penile behavior,” and “both men and women reported that, in the wake of allegations of female cheating, men thrust deeper and faster.” Men also thrust deeper and faster after being reunited with partners they haven’t seen in awhile, which led Gallup and his team to conclude that men want to make sure their partners aren’t impregnated by the competition while they’re away or while they’re astray.
And last, but not least, Gallup had one more theory that gave me pause. According to his “semen displacement theory,” it would be possible for a woman (me) to get pregnant by a man (Ryan Gosling) she never had sex with. Let’s say Justin Timberlake was having super thrusty unprotected sex with Rachel McAdams, like, 24 hours after she had a super thrusty unprotected one night stand with Ryan Gosling. In the process of cleaning out all of the Gos’ sperm with his super thrustiness, some of Ryan’s sperm could feasibly get forced under Justin’s frenulum, collecting behind his coronal ridge. A few hours later, Justin and I meet at a club and end up having super thrusty unprotected sex. When he ejaculates some of Ryan’s sperm could get mixed up with his and shoot into my baby maker, potentially resulting in conception by one or BOTH (fraternal twins from different fathers, holla!).
Original by: Amelia McDonell-Parry