When embarking on your family-building journey, you will inevitably think about how many children you ideally want — and what sexes they might be. But can you choose the sex of your baby?
Let’s explore how a baby’s sex is determined, the truth behind the old wives’ tales about having a boy or a girl, and the only way you can really choose the sex of your baby.
Legacy recognizes that gender and sex are separate concepts, but we’re using common language here. When we refer to conceiving a boy or a girl in the following article, we mean conceiving a baby with XY or XX chromosomes.
Key takeaways:
🌸A baby’s biological sex is determined by whether their father’s sperm contained an X chromosome or a Y chromosome. XX is genotypically female, while XY is genotypically male.
🌸There are many ideas about ways to influence baby’s sex and how to conceive a boy or a girl, but these are mostly myths or “old wives’ tales” that aren’t supported by modern science.
🌸The only reliable way to choose a baby’s sex is by using IVF with genetic testing. This process has financial and emotional considerations.
How is a baby’s sex determined?
Every human cell has 23 pairs of chromosomes (46 total chromosomes). Half of these are from the biological father’s sperm, and the other half from the biological mother’s egg.
Two of these chromosomes (X and Y chromosomes, also known as sex chromosomes) determine a baby’s sex. One X chromosome always comes from the egg, and the second — which can be X or Y — comes from the sperm.
If the sperm that fertilizes an egg has an X chromosome, the baby will be a girl (XX genotype). If it has a Y chromosome, it will be a boy (XY genotype). It’s the sperm that chooses the baby’s sex.
You can find plenty of people who will say that the method worked for them, but does the science support that?
Blogger Genevieve Howland at Mama Natural is one who says that the Shettles method helped her sway for a girl with her second pregnancy. She and her husband timed sex 3 days before ovulation and the pregnancy did result in a girl. She explains further that with her first pregnancy, they had sex right on the day of ovulation, which resulted in a boy.
This one case study aside, Shettles claims an overall 75 percent success rate in the current edition of his book.
Not all researchers agree that things are so cut and dry, however.
In fact, a 1991 review of studiesTrusted Source refutes Shettles’ claims. In those studies, researchers also took into account the timing of sexual intercourse, as well as markers of ovulation, like basal body temperature shift and peak cervical mucus.
The studies concluded that fewer male babies were conceived during the peak ovulation time. Instead, male babies tended to be conceived in “excess” 3 to 4 days before and in some cases 2 to 3 days after ovulation.
A more recent study from 2001Trusted Source refutes the idea that X- and Y-containing sperm are shaped differently, which goes directly against Shettles’ research. And an older study from 1995 explains that sex 2 or 3 days after ovulation doesn’t necessarily lead to pregnancy at all.
