THE NUB THEORY EXPLAINED
All nubs will image as a fork. This fork is split into two parts. The bottom half, also known as the urogenital folds will develop into the labia minora, and the top half will develop into her clitoris.
For male fetus the genital tubercle will develop into the glans of the penis,
the urogenital fold becomes the shaft and the labioscrotal fold matures into the scrotum.
At your NHS dating scan at around 12 weeks, your sonographer will be able to capture a clear shot of your baby's nub, (if they are a believer in the nub theory) if not you can ask for a side profile shot of your baby, this will most likely show their nub.If your baby is showing a clear nub shot, the accuracy of your prediction will be extremely high, up to 99.9%.
It is rare for a nub theory prediction to be incorrect by our team, especially if a fully imaged nub has been captured. If this does happen, its usually when the baby's gestation is early, if at around 12-12.2 weeks, his nub may have presented parallel, this means his genitals may have taken a little later to develop (a late riser).
NUB THEORY GIRL
LONG, FLAT AND TUBED NUB
The developing female nub varies at different gestations, the nub here is parallel to her spine, it also sits below 30 degrees and you will also find her nub hangs directly off her rump.
We often get asked, if a nub is showing as a fork it has to be a girl, is this right? This information is actually incorrect. As you can see from our examples, we illustrate how a male nub is angled above 30 degrees, you can also see the tip of his nub points upwards indicating a baby boy. We also illustrate a female nub shot which is angled below 30 degrees, the nub points downwards and sits flush to her spine indicating a baby girl.The length and shape of your baby's nub may sometimes indicate gender, but not always.
For example, some say that a “forked nub” is indicative of a girl fetus, however we do not adopt this, as its clear that both sexes can be seen with a forked nub in the early stages of development. The reason you see a fork shaped nub in both female and male fetuses, is because this fork serves an important purpose. For females, this fork will become the labia and clitoris, for males, the top half of the fork will develop into the penis, and bottom fork into the scrotum.We also know a forked nub is a sign of an undeveloped nub or a late riser (in males)
GENITAL TUBERCLE AT 12 WEEKS
CREDIT - SCIENCE SOURCE