Long before modern genetics, humans concocted wild, agonizing, and hilarious schemes to guess whether they’d have a boy or a girl.
We’ve all heard the old wives’ tales whispered at baby showers. People swear that carrying low means you’re having a boy, while wicked morning sickness guarantees a girl. But historically, folks didn’t just guess; they took matters into their own hands with unbelievable intensity.
According to the World Health Organization (WHO), nature sets the baseline at roughly 105 boys born for every 100 girls, giving live births a natural split of about 51.2% boys and 48.8% girls. That near-even split wasn’t good enough for our ancestors, who were desperate for male heirs or specific family lines. To beat the odds, they turned to bizarre medical theories that will make you cringe and laugh.
Cutting Off the Left Testicle in 18th-Century France
French men in the 1700s underwent extreme surgery because they mistakenly believed male and female seed lived on opposite sides of the body.
In 18th-century France, an anonymous medical manual titled L’Art de faire des garçons (“The Art of Making Boys”) laid out a terrifying piece of advice. The author claimed that female offspring came strictly from the left testicle. Therefore, if a man truly wanted an heir, he had to surgically remove his left testicle.
This wasn’t just a bizarre French obsession. The theory originated with ancient Greek philosophers like Anaxagoras, who argued that right-side fluid made boys and left-side fluid made girls. In ancient Rome, Pliny the Elder told farmers to tightly tie off an animal’s left testicle to sire male livestock, a trick desperate men tried on themselves.
Tragically, these men endured painful, unsterilized mutilation for nothing. As modern reproductive biology proves, both testicles produce millions of sperm carrying either X or Y chromosomes, making the surgery completely pointless.
Smearing Goose Grease and Hiding Parsley
Ancient Roman physicians prescribed poultry fat and surprise garden herbs to sway the gender of unborn babies.
Galen of Pergamon was the undisputed medical heavyweight of the Roman Empire, but some of his ideas read like a fantasy novel. He claimed that if you rubbed a woman’s entire body with greasy goose fat for two straight days, intimacy on the third day would guarantee a baby boy.
If that wasn’t weird enough, Galen also placed great faith in parsley. He instructed hopeful parents to sneakily drop a sprig of fresh parsley onto a pregnant woman’s head without her noticing. Supposedly, the baby’s sex was decided by the gender of the very next person she spoke to.
If a couple wanted a daughter instead, Galen recommended tying a simple black ribbon around the woman’s left foot. None of this worked, of course, but it shows how far people went to feel in control.
Drinking Ground Hare Organs in Medieval Wine
A famous 12th-century Italian medical compendium convinced couples to drink powdered rabbit genitalia before jumping into bed.
In the medieval city of Salerno, female physician Trota and her colleagues compiled The Trotula, one of the most influential medical texts on women’s health. Tucked between recipes for herbal baths was an eye-watering potion for conceiving a son.
The text instructed the husband to take the hare testicles, dry them into dust, mix the powder into wine, and drink it down. Meanwhile, the wife took dried, powdered womb and vagina of a hare in her own glass of wine right after her menstrual cycle.
Rabbits were famous symbols of fertility, so medieval doctors thought consuming their reproductive organs transferred that biological energy. It was a stomach-turning cocktail that merely added gross flavors to vintage wine.
Related: 7 Harsh Reasons Your Husband May Pull Away During Pregnancy
Pointing Your Bed North to Catch the Chill Wind
For centuries, folk healers believed magnetic directions and breezy drafts could influence an embryo’s gender.
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If drinking powdered hare organs sounds too messy, you could always just rearrange the furniture. In the Babylonian Talmud, Tractate Berakhot 5b, Rabbi Yitzhak taught that couples who aligned their marital bed along a north-to-south axis would be blessed with sons.
European weather lore took this concept outdoors. Until the 17th century, people believed a crisp northern wind during intimacy guaranteed a son, while a southern breeze brought a girl. Couples routinely checked weather vanes and propped open bedroom windows to invite the proper draft. Sadly, breezy bedrooms only brought runny noses, not male chromosomes.
Peeing on Barley Seeds in Ancient Egypt
Egyptian papyri dating back nearly 3,500 years used sprouting grain bags as the world’s very first gender predictor.
Ancient Egyptian medical papyri from roughly 1350 BCE detailed a surprisingly sophisticated home test. Expectant mothers were instructed to urinate into two separate bags: one filled with barley seeds and the other with emmer wheat. If the barley sprouted first, a boy was on the way; if the wheat grew, parents prepared for a girl.
Remarkably, modern scientists tested this exact ritual in 1963 to see if the ancients had figured something out. The researchers discovered that pregnant women’s urine successfully caused the grains to sprout 70% of the time, driven by elevated estrogen levels. However, when it came to predicting fetal gender, the test failed completely with a 0% statistical correlation.
Starving for a Son in the Victorian Era
Victorian medical theorists incorrectly labeled boys the ‘starved sex’ and told pregnant women to skip meals.
During the 19th century, popular health writers convinced expectant mothers that boys were cheaper for the body to build. They advised women seeking sons to cut calories and endure severe fasts.
Modern science has shown the Victorians were completely wrong. A landmark study by the Universities of Exeter and Oxford tracked 740 pregnant women and found that 56% of mothers on high-calorie diets had boys, compared to just 45% in the low-calorie group.
Lead author Dr. Fiona Mathews explained: “If a mother has plentiful resources then it can make sense to invest in producing a son… However, in leaner times having a daughter is a safer bet.”
From Magic Potions to Modern Fertility Labs
Today’s parents no longer drink strange brews, relying instead on microscopic lasers and genetic testing.
For ordinary, unassisted conception, the biological odds remain an unpredictable coin flip governed by X- and Y-bearing sperm. But in modern fertility clinics, guessing is a thing of the past.
Using Preimplantation Genetic Testing for Aneuploidy (PGT-A) during IVF, embryologists can identify an embryo’s sex with over 99% accuracy before implantation. Older sperm-sorting techniques like the Ericsson albumin column and MicroSort offered lower success rates of roughly 70% to 88%.
This technology has ignited fresh ethical debates. The American Society for Reproductive Medicine (ASRM) warns that using genetic screening solely for elective “family balancing” raises complex questions about social equity and reproductive fairness.
The Grand Biological Sum-Up
Folklore promised total control over baby gender, but nature has always guarded its near-even balance.
Humanity spent thousands of years rubbing fat, swallowing crushed rabbit parts, and turning beds toward cold winds. None of it moved the needle past nature’s stubborn 50-50 odds. While high-tech fertility treatments finally give parents real choice, the ancient stories remind us how deeply humans yearn to outsmart biology.
What crazy old wives’ tales or gender-prediction rituals have your own family members sworn by, and did the results actually match the legend?
