Theories abound about how would-be parents can influence the sex of their future child, from following a certain diet to using certain sexual positions or the timing of intercourse. And you can even buy a natural gender selection kit online that claims to be FDA-approved, with 96 percent success rate—or your money back.
For centuries, couples have been told that there are secret tricks to conceiving a child of the preferred sex. The most dangerous—and painful—method ever proposed was Artistole’s recommendation that a man who wants to father a boy should tie off his left testicle before sex. The ancient Greek philosopher believed that the right testicle produces male sperm and the right produces female sperm, a myth that continued to circulate until the 18th century.
Today, a variety of seemingly scientific methods are pitched to parents who want to sway the usual 50/50 odds, to balance their family, fulfill a dream of having a son or daughter, or to prevent their child from inheriting a sex-linked genetic condition. But do any of them actually work? Here’s a look at three natural gender selection plans and what science says.
The theory: Developed in the 1960s by Landrum Shettles, MD, this strategy is based on the theory that Y sperm are faster swimmers, but are also shorter-lived and less likely to survive in an acidic environment (the pH level of the vagina and cervix). Basically, boy-producing sperm live fast and die young. The plan is designed to exploit purported differences between the two types of sperm.
How it works: Couples who want a boy are advised to abstain from sex during the four to five days before ovulation, then make love once on the day the egg is released, so the speedy Y sperm will reach it sooner. The method recommends deep penetration (rear-entry positions) to get Y sperm closer to the cervix and the egg. Ideally, the woman should have an orgasm, which according to Dr. Shettles, makes the vagina more alkaline to favor Y sperm.
To conceive a girl, couples are told to make love two or three days before ovulation, using shallower penetration (the missionary position), and women should avoid orgasm.
Is it effective? Proponents claim the method is 75 to 95 percent successful, but a 1995 study published in the New England Journal of Medicine found that the timing of sex relative to ovulation has no influence on the sex of the baby. Another study reported that following the Shettles Method’s advice for having a girl was slightly more likely to result in a boy.
The theory: First popularized in 1982 by the book The Preconception Gender Diet, by Sally Langendoen, RN and William Proctor, the theory holds that what a woman eats before getting pregnant influences the baby’s sex by altering the body’s pH balance.
How it works: Women hoping for a boy are advised to eat salty foods like olives and bacon (to a max of six grams of salt daily), while restricting foods containing calcium (like milk, yogurt, tofu, and fortified orange juice and cereals) and magnesium (such as fish, bananas, most nuts, soybeans and spinach). Conversely, women who want a girl should load up on foods that are high in calcium and magnesium, while limiting salty ones.
Is it effective? A small study by researchers at Gender Select in the Netherlands found that among women who ate a low-salt, high-calcium diet, combined with timing intercourse well before ovulation, 81 percent delivered girls. However, the study only tracked 32 women who fit a “prediction rule” that the researchers devised, so the results might also be due to chance or faulty methodology.
The Mayo Clinic advises women who are planning to get pregnant to eat a diet rich in folate and folic acid to reduce the risk of neural tube birth defects (such as spina bifida), and also recommends plenty of calcium and vitamin D (to build strong bones and teeth).
The theory: Taking certain dietary supplements, plus timing intercourse, equals a baby of the preferred sex.
How it works: Natural gender selection kits typically include certain supposedly gender-specific “neutraceuticals” (dietary supplements), plus a thermometer to track ovulation, and instructions on how to time sex. One such kit, sold online by GenSelect, costs $439 for a 3-month supply of the supplements, or $329 for two months.
Is it effective?
The GenSelect website states that its kits are “96 percent effective in preconception gender selection when directions are followed,” but doesn’t cite any independent randomized clinical trials or other studies to support this claim. Some items in the kit, such as the basal temperature thermometer, are FDA-approved, but the kit itself doesn’t appear in a search of the FDA’s database of approved medical devices.
Michael Zasloff, dean of research at Georgetown University Medical Center, says that claims made by makers of gender selection kits are “unbelievable,” and contends that the notion that dietary supplements can influence gender is “absolutely absurd” and without any scientific merit, according to the Chicago Tribune.
Get the information you need to improve your health and wellness on Healthline.com.
Signs of Depression. Learn how to tell the difference between a bad day and something more serious.
Famous Faces of Depression. Learn about those who rose to fame despite feeling extremely low.
Improve Sexual Performance. Learn healthy ways to get in the mood and last longer between the sheets.
Treat Psoriasis at Home. Follow these helpful tips to manage your condition every day.
Human Body Maps. Check out the human body in 3D.