9 Surprising Facts About the Scientific Study of Sex

vadimguzhva/iStock via Getty Images
vadimguzhva/iStock via Getty Images

The scientific study of sex is much more exciting than an awkward sex ed class. While writing my book Sex Weird-o-Pedia, these were some of the most interesting facts about science and sex that I came across.

1. Some sex researchers didn't want their findings to get into the wrong hands.

The pioneering sex researcher Richard von Krafft-Ebing didn’t want his knowledge in the hands of ordinary folk. So he wrote Psychopathia Sexualis, the founding document of modern sexology—which was published in Germany in 1886 then translated and published in English in 1939—in Latin to discourage regular Joes (and/or Janes) from reading it.

2. You burn more calories mowing the lawn than you do having sex.

Young woman poses for selfie while mowing the lawn
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Sex might seem strenuous when things get hot and heavy, but it's usually not that great of a workout. You'd have to go at it for nearly 200 minutes to burn as much energy having sex as you do during a 30-minute run. Even mowing the lawn burns about three times more calories than sex. According to the British Heart Foundation, sex burns about the same amount of energy per minute as ironing clothes.

3. A surprising number of mothers claim to be virgins.

In a 2013 study of several thousand pregnant women in the U.S. published by BMJ, about 1 percent of the participants claimed they were virgins when they gave birth. This, of course, calls into question the veracity of studies that rely on self-reported sexual behaviors.

4. Penicillin may have ignited the sexual revolution.

One economist says that penicillin, and not the birth control pill, was the real enabler of the sexual revolution. A study published in the Archives of Sexual Behavior in 2013 shows that penicillin contributed to a 75 percent decline in the number of deaths caused by syphilis from 1947 to 1957. Since the new treatment made sex safer, people started having riskier sex, which resulted in increases in the numbers of children born out of wedlock and teenage pregnancies.

5. Twins can have different dads.

A photo of fraternal twins
Aleksandr Zhurilo/iStock via Getty Images

While it is very rare, it is possible for fraternal twins to have two different fathers. What’s more common is for a rom-com to be based on this scenario.

6. Gender may influence how people handle sexual jealousy.

Research from evolutionary psychologists indicates that people’s gender influences how they react to sexual jealousy. For men, they react more strongly to sexual unfaithfulness than emotional infidelity. For women, it is the reverse. The theory behind these behaviors comes back to evolution: Males who were intolerant toward their wives becoming sexually active with other men were less likely to become an object of derision and more likely to see their own genes pass onto future generations. Women who prevented their husbands from emotionally bonding with other women reduced the chances of the men spending their resources on other women.

7. One of Ivan Pavlov's colleagues created his own (slightly x-rated) conditioning experiment with dogs.

You’re probably aware of Russian researcher Ivan Pavlov and his famous conditioning experiment in which he trained a dog to salivate at the sound of a bell. What you might not know is that one of Pavlov’s American students, W. Horsley Gantt, conditioned dogs to become sexually aroused when they heard specific tones. The experiment, according to Mandy Merck's In Your Face: 9 Sexual Studies, was intended "to study conflicts of the drives between ... experimentally induced anxiety states and sexual excitement."

8. Couples whose first child is a girl are more likely to get divorced.

Parents pay attention to their phones instead of their daughter
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Married couples whose first child is a girl are more likely to get divorced than those whose first child is a boy. Scientists are split as to why this is. One theory is that female embryos are better able to endure maternal stress than male embryos, so pregnant women in unhappy marriages are less likely to have a miscarriage if the child they are bearing is a girl. But once they have a daughter, these couples are more likely to split up since there were already fissures in their relationship prior to the child’s birth.

9. There's a link between pubic hair and STIs.

A downside of pubic grooming is that it might raise STI risk. In a study conducted by a University of Texas scholar, people who regularly shaved their pubic areas contracted STIs about 80 percent more often than those who never shaved down there. One suggestion is that those who regularly shave are more likely to tear their skin, making it easier for viruses to enter the body.

Ross Benes is the author of Sex Weird-o-Pedia: The Ultimate Book of Shocking, Scandalous, and Incredibly Bizarre Sex Facts.

The Best Place to Park at the Mall, According to Science

Diy13/iStock via Getty Images Plus
Diy13/iStock via Getty Images Plus

It’s Black Friday, and you are entering the battlefield: a mall parking lot. You’re determined to nail that doorbuster deal, and quantities are limited. The field is already full of other combatants. You must find the perfect parking spot.

Do you grab the first one you see, or drive as close to the mall as you can and hover? Or, do you choose a tactic that lies somewhere between?

Parking at the mall has long frustrated drivers and taxed the minds of traffic engineers—but after working on the problem for three years, physicists Sidney Redner of the Santa Fe Institute and Paul Krapivsky of Boston University have gotten closer to a winning strategy. “There are lots of studies of parking lots, but it’s just that they’re so complicated, you don’t get any insight into what’s actually happening,” Redner tells Mental Floss.

Redner and Krapivsky, whose work employs statistical physics to make sense of large systems, simplified the messy dynamics of a parking lot by modeling it with a one-dimensional grid of cells, each representing a parking space. They tested three simple, yet realistic, parking strategies using basic probability theory. Their model tested the following strategies to see which one resulted in least time spent walking and driving in the parking lot:

Meek Strategy: Meek drivers park in the first open space they see, however distant it is from the mall. As a result, they often spend the most time walking to and from the mall.

Prudent Strategy: Prudent drivers look for the first open spot but then keep driving toward the mall. They continue to drive until they see a parked car and then park in the best open spot between that first open spot and that first parked car. There may be a block of open spaces between the first open space and the first parked car. From that block of open spaces, they choose the one closest to the mall.

Optimistic Strategy: Optimistic drivers drive as close to the mall as possible and look for a parking space close to the entrance. If they see one, they grab it. If there are none, they backtrack and choose the first open space they see. Optimistic drivers probably spend the most time driving and the least time walking. In the worst-case scenario, they end up parking back where a meek driver would have parked.

Naturally cautious drivers are more likely to default to the meek mode, while aggressive drivers often use the optimistic strategy, well, aggressively. And most drivers have tried something like the prudent method.

So, which is your best bet in a crowded mall parking lot this holiday season?

In the experiments, the prudent strategy fared best, followed closely by the optimistic strategy. The meek strategy finished a distant third (“It’s hard to comprehend just how bad it is,” says Krapivsky, a self-described meek driver).

And even better: The more crowded the lot, the better the prudent strategy works, he adds.

One clear takeaway from the study is that meek drivers may want to ramp up their parking skills before going to the mall. “You don't want to park on the very outskirts of the lot, like a mile away from the stores. You want to go to the first place there’s an open spot and park somewhere in that first open area,” Redner says. They published their findings in the Journal of Statistical Mechanics [PDF].

The researchers say this is the best of the strategies they tested, but it has its limitations. It does not take into consideration competition among a sea of drivers all looking for parking spaces at the same time, and it doesn’t include (perhaps optimistically) the psychological aspects of operating a vehicle. “We are not rational when we are driving,” Krapivsky tells Mental Floss.

The researchers’ one-dimensional grid model also assumed that there would be one car at a time entering the lot through one entrance, unlike messier lots in the real world, where many cars enter from a multitude of entrances.

The optimal parking strategy, one that would best all others every time, has yet to be found. In their research, though, Redner and Krapivsky are homing in on one that integrates the more complicated aspects of parking.

For now, science says prudence is a virtue in the parking lot. And while the meek might inherit the Earth, they certainly won’t find the best parking space at the mall.

'Lost Species' of Tiny, Rabbit-Sized Deer Photographed in Vietnam for the First Time in 30 Years

Global Wildlife Conservation
Global Wildlife Conservation

The silver-backed chevrotain, also called the Vietnamese mouse-deer, is elusive. It's so elusive that scientists had feared it was extinct after none had been photographed for decades. But as The Washington Post reports, the first images taken of the mammal in nearly 30 years prove that the species is still alive in the woods of Vietnam.

No larger than small dogs, chevrotains are the tiniest ungulates, or hoofed animals, on Earth. They have vampire-like fangs and skinny legs that support their bodies. Silver-backed chevrotains are characterized by the silver sheen of their tawny coat.

The tiny population native to Vietnam has been devastated by poachers in recent decades. That, and the animal's natural shyness, make it incredibly difficult to study. Before this most recent sighting, the last time scientists had recorded one was in 1990.

Global Wildlife Conservation, the Southern Institute of Ecology, and the Leibniz Institute for Zoo and Wildlife Research teamed up in hopes of documenting the lost species. Researchers interviewed residents and government forest rangers in the Vietnamese city of Nha Trang about the silver-backed chevrotain, looking for tips on where to find one. Residents said that while populations had been hit hard by hunting, the animals were still around.

Based on this local ecological knowledge, scientists set up three camera traps in the Vietnamese woods. In just five months, they captured 275 photographs of the little mouse-deer. They then installed 29 additional cameras and snapped 1881 new images in that same length of time.

“For so long this species has seemingly only existed as part of our imagination," Global Wildlife Conservation associate conservation scientist An Nguyen said in a statement. "Discovering that it is, indeed, still out there, is the first step in ensuring we don’t lose it again, and we’re moving quickly now to figure out how best to protect it.”

Now that a silver-backed chevrotain population has been located, researchers plan to conduct the first-ever comprehensive survey of the species. Once the data is collected, it will be used to build a plan for the species' survival.

[h/t The Washington Post]

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