You can’t beat a 98% accuracy rate!

When my sister was pregnant with her first baby, she and her husband didn’t want to know if it was a boy or girl. They wanted to wait until delivery.
Along the way, though, she had several premonitions telling her it was a boy:

* She just had “a feeling”. This was her number one explanation.
* She had dreams of having a baby boy.
* Her father in law had a dream it was a boy.
* My favorite: the owner of their favorite chinese restaurant took one look at her pregnant belly, pointed, and said, simply, “boy”.
It turns out, they were all right. At birth, the doctor’s first words: “it’s a boy” was not so surprising after all.

At that time, I read a study about women being able to predict the gender of the fetus in utero. When women wanted to wait until delivery to find out the gender, like my sister, they were asked why. The most common reason, as anyone could have guessed, was they “wanted it to be a surprise.” The second reason given was pure superstition – they would be happy with a healthy pregnancy regardless and thought it was bad luck to learn the gender.

Women guessed the correct sex 55% of the time. In another similar study several years back, women were right 70% of the time. If a woman can predict the sex of the baby, more than a 50/50 chance, how do they tell?
* In this study, women with more than one pregnancy compared the pregnancy to a previous one. If it felt the same, it was the same gender as her first baby. If it was different, it was the opposite gender.
* In first time mothers, the most common single reason was simply intuition – “just a feeling”.
* The way a woman was carrying the baby (high or low) was the next most common way.
* Some women had dreams (only 14% claimed this was their “sign”), or based their guess on fetal activity (10% of women).

As a side not, folklore says if a woman carries the baby high, it is a boy. Women in the study often misapplied folklore though. Some women said they could tell it was a girl because the pregnancy was being carried high. I’m not sure if this counts as random luck they got the sex right, or if it was their intuition being explained by a physical finding.

Routine prenatal care includes an anatomy ultrasound around 18 to 20 weeks. The genitalia, and therefore gender, can be seen at this time. An experienced ultrasonographer will be right 95% of the time … so when your ultrasound shows a boy, but your dream the night before told you it was a girl, I would go with the ultrasound.

Article: Perry, D et al. “Are Women Carrying “Baseketballs” Really Having Boys? Testing Pregnancy Folklore”. Birth 26:3 September 1999