Nub Theory Explained
What is a Nub? And what the heck is this Nub Theory?
A nub is a small protuberance seen between the legs at as early as 9 weeks. Both boys and girls start with a flat ambiguous nub (which is why most boys can be inaccurately guessed as girls during the 11th gestational week)
The nub is a fact. All babies have a nub and how they develop is also science and fact. It is how we try and decipher the ultrasound image of the nub to correlate with this fact is what equals the nub theory.
Sounds easy peasy, right? Most nubs in ultrasound images are not as cut and dry as that unfortunately, but that is where we can help. Used with a perfect mid line image of baby the nub usually can image pretty perfect...but perfect is rare. Some nubs are tricky -they are angled in "the grey zone" where it can go either way and that is usually due to the gestation of baby.
But first lets try and understand what the nub is and what we look for!
Simple form: I will try to refrain from getting all medical terminology-y trying to understand on how these itty bitty bits we refer to as baby’s nub actually develops and compare it to easy and practical terms that anyone could understand instead. Hopefully! Fingers crossed!
If you have a basic understanding of what boys and girls have, you have a good start. Basic mature developed genital premise: Girls' clitoris are enveloped by the labia and stay straight out pointing to our dainty little feet and Boys penis' (peni) remain outside of the body and sometimes like to rise up, pointing straight up or towards their big wonderful man brains. This right here is the very core of the nub theory and angle of the dangle. Straight and flat pointing out toward the feet = girlish…rising or pointing up at a relative angle = boyish. I always like to say that genitals are like snowflakes, no 2 are exactly alike! See? Even your 90 year Grandpa could understand this!
Another easy thought to remember is that penis and clitoris develop from the same tissue. As does the labia and scrotum. Hormones and wonderful Mother Nature play their part in the 12th week to distinguish baby for the rest of their lives with their genitals. So fun! Scrotum fuses together (and why scrotum has a seam down the middle) which makes the boys nub (developing penis) rise up. Labia keeps separating to envelope the receding clitoris. And why a girlish nub stays flat and will sometimes look to be hanging off their cute bums. It really is as easy as that.
As mentioned above this "grey zone" is usually seen between 12w0d - 12w3d. All babies develop at different rates, please keep this in mind! We go by the usual and average and as such there is always exceptions to this. We have had some over achievers (early developers) and some slackers (just liked to take their time developing) Just like every human, we are all different, as are developing babies. Since we are dealing with "parts" that are so tiny at this stage; if baby has their little bottoms turned even just a hair left or right, the sound waves can completely not reflect off certain parts of the nub.
Ultrasounds image in slices. Imagine a loaf of sliced bread. Baby is the loaf of bread. Each slice is a slice of image of baby's body. Exactly how ultrasounds work. The image plane we use to look at the nub is mid-sagittal, which means the loaf of bread is sliced long ways.
Gender guessing with the nub increases in accuracy as you hit 13 weeks, and is at its very lowest of accuracy in the 11th week.
Also, any of us experts are always available if you have any questions! We are always just a PM away
Example boy nubs. Keep in mind these are perfect nub shots
Great "stacked" nub: one on top of the other (developing penis on top, scrotal line underneath)
Again, perfect nub images
You can also look at all our wonderful members babies from the years and their confirmed nubs and potty shots at this link:
To post your own images for predictions, follow this link here ----> Post Your Ultrasound Images Here!