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9 Historical Methods for Determining the Sex of an Unborn Baby

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Are you pregnant? Do you like eating poultry and venison, and talking about jousting and knight stuff? Well, then you’re obviously carrying a boy. Like dancing and music? It’s a girl.

Sure, it’s not the most scientific of determinations, but for women living in a world before ultrasounds, there was no way to tell just what or who or how many were in there. Modern technology has made a window into a place which, for hundreds of thousands of years, only speculation illuminated.

So, if you don’t have the benefit of that window (which, by the way, isn’t always clear), how did you tell whether you were carrying a boy or a girl? And perhaps even more important, could you choose which?

Before we get to the good stuff, here’s a quick Bio 101 primer on how it really works: Human sex differentiation is dictated by the XX/XY system. The egg cell (we’ll call her Sally) contains one lady-making X chromosome; the sperm (let’s call him Harry) can carry either an X or a Y chromosome. When Harry meets Sally (see what we did there?), whether they’ll make a boy or a girl is dependent on which chromosome Harry’s packing. The Y chromosome stimulates testis formation in the fetus, and thus male sexual development; no Y chromosome, the gonads become ovaries and you’ve got yourself a girl. Pretty simple (except when there’s an anomaly, such as Klinefelter’s syndrome, an extra X chromosome attached to the XY that can manifest in decreased fertility, increased breast tissue, and other ways). The sex of the infant is set, though possibly not in stone, as soon as the sperm fertilizes the egg, but the sexual bits don’t develop for several weeks. Most parents don’t find out their baby’s gender until the 20-week scan, if they do find out at all. 

1. Ways to Game the System

So making a boy or a girl the old fashioned way is a bit of a crapshoot—it’s whichever sperm survives the cervical gauntlet. Nowadays, fertility specialists can make and identify embryos of either sex, but it’s generally frowned on (and illegal in the UK, except in cases in which you have a serious genetic condition that you risk passing on to a child of a certain sex).

But not really having a ton of control over the situation didn’t and doesn’t stop women from trying to game the system. The Distaff Gospels is a collection of medieval European women’s medical lore recorded in the late 15th century; it’s also responsible for the above gender stereotyping about jousting and dancing. The Gospels recommended having the man turn his face towards the east during sex if the couple is trying for a boy; to have sex in the morning if you’re aiming for a boy and in the evening and night if you want a girl; or not to have sex right after a meal if you want a boy. Another medieval source recommends that the gentleman quaff a cocktail made of red wine and pulverized rabbit’s womb, while the lady do shots of red wine and dried rabbit’s testicles.

Of course, if you want to try for a particular sex (say, if you’re modern royalty tasked with producing a son and heir), then there are couple things that you can do. There’s the Shettles method, based on the notion that Y-toting sperm are faster swimmers than X-toting sperm, but don’t live as long. If you want a boy, then, you should try to have sex as close as possible to ovulation, to give the male sperm a fighting chance; if you want a girl, you should have sex two to four days before you ovulate. There’s also the Whelan method, which is kind of the opposite: If you want a boy, you should have sex four to six days before you’re about to ovulate and if you want a girl, two to three days before. The Whelan method is predicated on the idea of basal body temperature affecting sex determination.

Once the egg is fertilized, however, how do you know what you’ve got in there without the benefit of a window?

2. The way you walk

Walk with your right foot first, you’re having a boy; the opposite, you’re having a girl. This was according to the Distaff Gospels again—a wonderful source for medically questionable stunners, some of which were, if not exactly prescient or accurate, at least well-intentioned: For example, the Gospels cautioned that if at the hour of conception, “neither feels affectionate love for the other, a female of bitter disposition is born.”

3. The salt test

The Gospels again: “When a woman is carrying a child and she wishes to know whether she is carrying a boy or a girl, you should sprinkle salt on her head while she is sleeping, so gently that she is unaware of it. When she wakes, note what name she says first. If she says a man’s name it will be a boy and if she says a woman’s name it will be a girl.” Or maybe she’ll just wake up saying the name of the weirdo who put salt on her head.

4. Ask Mom

“If a pregnant woman wants to know the gender of the child she is bearing, listen to her and she will reveal it herself,” the Gospels said. “When she asks: ‘What do you think I am carrying?’, if you say: ‘A lovely boy’, and she does not blush, you should know for sure that she will have a girl.”

Blushing aside, there is some evidence that women have a sort of mother’s intuition about what’s going on in there: According to The Sun, a study found that women with no prior knowledge of their baby’s gender guess the sex correctly 71 percent of the time. Presumably, these researchers did not ask the mothers-to-be by using the “key test”—place a key in front an expecting mother and if she grabs it by the fat end, she’s having a boy, and by the narrow end, a girl.

5. Morning sickness

This is one of those old wives’ tales that is not only literally an old wives’ tale (the women in the Distaff Gospels were old and wives), but is also believed today—the idea that how and when you are sick when you’re pregnant can give some clue as to whether it’s a boy or a girl. According to the Gospels, you’re sicker in the first three months with a girl than with a boy, but a boy causes pain after the first trimester. But according to current medical professionals, if you suffer badly from morning sickness (a horrible misnomer if there ever was one) or are ill throughout your pregnancy, you’re more likely to be carrying a girl.

6. Fat daddy?

According to myth, if the father piles on the pounds during the mother’s pregnancy, then she’s carrying a girl; interestingly, Danish researchers conducted a study of 100 fathers-to-be and discovered that indeed, those who had little girls were heavier at their births than those who had boys.

7. Sweet or sour?

Because girls are naturally sweet, if you’re carrying one, you’ll crave sweet foods; boys, being made of snips and snails and puppy dogs’ tails, make you crave sour and salty foods. Fact. (Except not really.)

8. One Ring to Bind Them…

When you’re not using your gold ring to enslave Middle Earth, you could possibly use it to determine the sex of your unborn child. Perhaps the most popular gender determination myth is that a gold ring suspended on a string over a pregnant woman’s belly will tell you what she’s carrying by how it swings: Side to side for a boy, circular for a girl. It’s not always accurate, of course, but will be right 50 percent of the time.

9. How you’re carrying

When I was pregnant with my son, we decided not to find out his gender; that occasioned a lot of people to inform me that they could tell whether I was harboring a blue or a pink based on how I was carrying. According to the very ancient lore, if you’re carrying a lower bump, it’s going to be a boy; if it’s higher, it’s a girl. According to the people who predicted my baby’s gender, he had a 50 percent chance of being a boy and 50 percent chance of being a girl, based on their scientific analysis. Thanks. How you’re carrying is not, scientists say now, a good indicator of your baby’s gender—it has more to do with your baby’s muscle tone, your personal shape, and even how old you are when you get pregnant.

Do you know any great baby gender determination old wives’ tales?

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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Scientists Think They Know How Whales Got So Big
May 24, 2017
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It can be difficult to understand how enormous the blue whale—the largest animal to ever exist—really is. The mammal can measure up to 105 feet long, have a tongue that can weigh as much as an elephant, and have a massive, golf cart–sized heart powering a 200-ton frame. But while the blue whale might currently be the Andre the Giant of the sea, it wasn’t always so imposing.

For the majority of the 30 million years that baleen whales (the blue whale is one) have occupied the Earth, the mammals usually topped off at roughly 30 feet in length. It wasn’t until about 3 million years ago that the clade of whales experienced an evolutionary growth spurt, tripling in size. And scientists haven’t had any concrete idea why, Wired reports.

A study published in the journal Proceedings of the Royal Society B might help change that. Researchers examined fossil records and studied phylogenetic models (evolutionary relationships) among baleen whales, and found some evidence that climate change may have been the catalyst for turning the large animals into behemoths.

As the ice ages wore on and oceans were receiving nutrient-rich runoff, the whales encountered an increasing number of krill—the small, shrimp-like creatures that provided a food source—resulting from upwelling waters. The more they ate, the more they grew, and their bodies adapted over time. Their mouths grew larger and their fat stores increased, helping them to fuel longer migrations to additional food-enriched areas. Today blue whales eat up to four tons of krill every day.

If climate change set the ancestors of the blue whale on the path to its enormous size today, the study invites the question of what it might do to them in the future. Changes in ocean currents or temperature could alter the amount of available nutrients to whales, cutting off their food supply. With demand for whale oil in the 1900s having already dented their numbers, scientists are hoping that further shifts in their oceanic ecosystem won’t relegate them to history.

[h/t Wired]

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