What Makes These Dominican Children Grow Penises at Puberty?

BBC via Youtube
BBC via Youtube

In the Dominican Republic, the phenomenon of children who were raised female appearing to swap sexes at puberty is so common it even has a name. Guevedoces roughly translates to "penis [or "balls"] at 12," and it’s the result of a rare enzyme deficiency that delays crucial steps of male sexual development until puberty.

When guevedoces are born, they appear to have external female genitalia even though their genes and internal reproductive organs are male. Parents assume their children are girls and raise them as such. But when these children begin producing large amounts of testosterone at puberty, their testes descend and they grow a penis—in addition to all the other changes that come along with male adolescence. 

Sexual development normally begins in the womb, and the same is true for guevedoces. Whether the fetus has one X chromosome or two, for the first several weeks of development its genes follow the same blueprint for both sexes. Then, sometime around the eight-week mark, the sex chromosomes get to work. For males, the undeveloped gonads become testicles and they start to release male hormones, including testosterone. In a structure called the tubercle, an enzyme called 5-alpha-reductase converts the testosterone to a stronger hormone called dihydrotestosterone (DHT), which is necessary to develop external genitalia. It's this hormone that turns the tubercle into a penis; without it, it develops into a clitoris.

The rare enzyme deficiency found in guevedoces leaves them unable to develop external male genitalia in the womb. They still produce plenty of testosterone, which triggers the development of internal structures like the epididymis and vas deferens, but the lack of DHT makes the babies appear female at birth. It’s not until the second surge of testosterone these children receive at puberty that they grow testes and a penis. 

The condition is thought to be genetic, tracing back to the female founder of a small village in the Dominican Republic's mountainous hinterland. Outside of the nation, it’s incredibly rare.

For some guevedoces, being raised as female wasn’t an easy experience. “I never liked to dress as a girl, and when they bought me toys for girls, I never bothered playing with them,” Johnny, who had grown up as Felicita, told BBC Two, which features these kids in the second episode of the series Countdown to Life: The Extraordinary Making of You. “When I saw a group of boys, I would stop to play ball with them.” When Johnny, now 24, began to undergo physical changes, he was taunted at school and called nasty names by his classmates. He’s had a number of short-term girlfriends since going through puberty and dreams of one day getting married and starting a family. Another child named Carla began the process of transitioning to Carlos at age 9; he can be seen receiving a smile-inducing haircut in the photo above. 

Most people with this condition live out their adult lives as men, but some choose to undergo surgery and remain female. The discovery of this disorder in the 1970s led to the development of a best-selling drug called finasteride, which is commonly prescribed to treat benign enlargement of the prostate and male pattern baldness. (You may know it by the brand name Propecia.) The drug mimics the enzyme deficiency by blocking the action of 5-alpha-reductase.

You can learn more about this rare condition and the people who have it on the BBC Two series Countdown to Life: The Extraordinary Making of You

[h/t: BBC]

Bad News: The Best Time of the Day to Drink Coffee Isn’t as Soon as You Wake Up

iStock.com/ThomasVogel
iStock.com/ThomasVogel

If you depend on coffee to help get you through the day, you can rest assured that you’re not the world's only caffeine fiend. Far from it. According to a 2018 survey, 64 percent of Americans said they had consumed coffee the previous day—the highest percentage seen since 2012.

While we’re collectively grinding more beans, brewing more pots, and patronizing our local coffee shops with increased frequency, we might not be maximizing the health and energy-boosting benefits of our daily cup of joe. According to Inc., an analysis of 127 scientific studies highlighted the many benefits of drinking coffee, from a longer average life span to a reduced risk for cancer, heart disease, type 2 diabetes, and Parkinson’s disease.

Sounds great, right? The only problem is that the benefits of coffee might be diminished depending on the time of day that you drink it. Essentially, science tells us that it’s best to drink coffee when your body’s cortisol levels are low. That’s because both caffeine and cortisol cause a stress response in your body, and too much stress is bad for your health for obvious reasons. In addition, it might end up making you more tired in the long run.

Cortisol, a stress hormone, is released in accordance with your circadian rhythms. This varies from person to person, but in general, someone who wakes up at 6:30 a.m. would see their cortisol levels peak in different windows, including 8 to 9 a.m., noon to 1 p.m., and 5:30 to 6:30 p.m. Someone who rises at 10 a.m. would experience cortisol spikes roughly three hours later, and ultra-early risers can expect to push this schedule three hours forward.

However, these cortisol levels start to rise as soon as you start moving in the morning, so it isn’t an ideal time to drink coffee. Neither is the afternoon, because doing so could make it more difficult to fall asleep at night. This means that people who wake up at 6:30 a.m. should drink coffee after that first cortisol window closes—roughly between 9:30 a.m. and 11:30 a.m.—if they want to benefit for a little caffeine jolt.

To put it simply: "I would say that mid-morning or early afternoon is probably the best time," certified dietitian-nutritionist Lisa Lisiewski told CNBC. "That's when your cortisol levels are at their lowest and you actually benefit from the stimulant itself."

[h/t Inc.]

26 Amazing Facts About the Human Body

Mental Floss via YouTube
Mental Floss via YouTube

At some point in your life, you've probably wondered: What is belly button lint, anyway? The answer, according to Mental Floss editor-in-chief Erin McCarthy, is that it's "fibers that rub off of clothing over time." And hairy people are more prone to getting it for a very specific (and kind of gross-sounding) reason. A group of scientists who formed the Belly Button Biodiversity Project in 2011 have also discovered that there's a whole lot of bacteria going on in there.

In this week's all-new edition of The List Show, Erin is sharing 26 amazing facts about the human body, from your philtrum (the dent under your nose) to your feet. You can watch the full episode below.

For more episodes like this one, be sure to subscribe here.

SECTIONS

arrow
LIVE SMARTER