For centuries, people have been proclaiming that they have the ability to predict the sex of a baby while it is still developing in the womb. Some people believe that the way a woman is carrying her baby can indicate the fetus’ sex as well as her mood, the state of her hair or skin, the existence of morning sickness, the color of her urine and even the position she was in when she got pregnant. However, these are merely old wives tales and have no bearing in reality.
Still, there has come into existence another theory in which a woman may be able to tell the sex of her baby as early as 12 weeks using an ultrasound scan. Until recently, a mom-to-be would have to wait until the 20-week scan or later to clearly see her baby’s genitals. Now, though, more sonographers are researching what is known as the “nub theory,” or the determination of a baby’s sex based on the “angle of the dangle.”
What is the Nub Theory?
Between 11 and 14 weeks’ gestation, males and females have a protuberance that resembles a penis between the legs. At this point, the bulge looks incredibly similar in both sexes except for the angle at which they are pointing. According to the nub theory, a girl’s “dangle” is 30 degrees or less relative to the backbone, and a boy’s “dangle” protrudes at a 30-degree angle or more when the fetus is lying straight on its back.
In order for a sonographer to have the most success of predicting the correct sex, the fetus must not be curled up; it needs to be lying on its back as flat as possible. The image must be taken from the fetus’ side as a profile shot, and it is often best if the fetus is right-side up.
Is the Nub Theory Accurate?
According to statistics, 11 weeks may be too early to use the nub theory to predict the baby’s sex. An ultrasound performed at 12 weeks is around 80 percent accurate while a scan conducted at 13 weeks may be closer to 94 percent accurate. However, solid scientific research into whether or not the nub theory is a valid method of predicting sex is yet to be undertaken, largely because most medical providers believe that it is just too early to accurately predict a fetus’ sex at 12 weeks.
Points to Consider
Some medical facilities simply will not allow sonographers to make any sex determinations at 12 weeks, and many prevent sonographers from informing families of the baby’s sex at 20 weeks. Instead, some clinics and hospitals prefer that a sonographer take images and present the findings to a radiologist before an accurate determination is made.
However, sonographers should be prepared to answer questions relating to the nub theory as more women are attempting to discover the sex of their child as soon as possible. While sonographers should not necessarily recommend that parents-to-be paint their nurseries in blue or pink based on the nub theory, these guessing games can help to add a little excitement to the pregnancy.