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Discover your baby’s gender from the start !

How Nub Theory can predict baby gender from 12 weeks scan

Are you pregnant, and you are both excited and curious to know if it is a baby boy or a sweet little princess on the way? Nub theory is now helping expecting mothers and parents to find out about the gender of their child.

In case this is the first time you have heard about the Nub Theory, this article will give you insight into how it works.

What is Nub Theory?

The nub theory is a medical method used by professional healthcare physicians to get an early prediction of your baby's gender from an ultrasound. The term nub theory came from the analysis of the "Nub." A Nub is also known as a genital tubercle, i.e., your child's indeterminate sexual organ.

Genital nub example on a fetal ultrasound

This genital tubercle of your child will grow into a penis or a clitoris defining their gender. Mostly, you can see it happening during the second trimester of your pregnancy. Ask your physician about it if you're expecting to go in for your 20 weeks' autonomy scan.

That said, if you are in the earlier stages of your pregnancy, the Nub will look the same in shape and/or size whether your baby is a boy or a girl.

The Difference between the Genders

Are you wondering how you can tell if it is a boy or a girl in a scan? The answer is simple, i.e., a boy's Nub will be pointing out in a different direction than a girl's Nub.

If you are expecting a baby boy, the Nub will angle upwards. On the other hand, if you are going to have a girl, the Nub will lie down flatter. Hence, another un-formal yet witty term used for nub theory is "the angle of the dangle" that reveals if the fetus inside you is a boy or a girl.

Variation of the Angle of the Dangle

The nub theory relies on analyzing the angle between your baby's spine and the Nub. Here is a short description of the variation.

The nub theory applied to a girl nub
The nub theory applied to a boy nub

Is Nub Theory Reliable to Determine Your Baby's Gender?

The nub theory first appeared back in 1989. Since then the several scientific studies in 1999, 2006, and 2012 have evaluated the accuracy of the method.

That said, the average reliability of the nub theory currently stands at more than 90 percent. However, it depends on the following conditions.

Although, the method is not 100 percent reliable if you get an ultrasound before 12 weeks of pregnancy. Why? Because the Nub will not be clearly visible until the 12th week so hold your horse and let the thing come out of its shell.

It is imperative for you to know that the nub theory prediction's accuracy rate will highly depend on the expertise of the physician or healthcare professional.

According to an ultrasound technician, she only got the gender wrong once in her 25-year career. (Unfortunately for her, it was her best friend's baby, so she will never escape that party joke).

Some healthcare technicians and professionals even admit not to dare reveal the prediction because they are not too confident about the nub theory. This is why BABYGRAM experts have to take a test to check their abilities and experience to provide reliable predictions for expecting mothers.

It Can Be Tricky to Predict the Gender

Sometimes the nub theory struggles to predict the gender of your baby. This is when the Nub shows two different angles in different positions. One picture of the baby's fetus may show a nub of a boy, whereas a picture taken from a different position may suggest it to be of a girl.

Partial view of a boy's genital nub
Partial view of a girl's genital nub

Same baby, two nubs! Yes, a girl and a boy can have a nub of the same appearance! See the examples below, which are great classics of cases that are very difficult to identify.

Nub theory can be wrong: different-looking nubs for the same baby girl
Limits of the nub theory: same-looking nubs but different genders

What's more, you cannot even see the Nub at all, or its appearance is of no particular gender, as shown in the photos below.

Boy or girl? Predicting the sex in such cases is a 50/50 game at best.

Limits of the nub theory: unclear examples of baby nubs

You must also remember that a nub analysis before 12 weeks of pregnancy, especially for fetuses smaller than 60mm, may be inaccurate. A flat nub indicating a girl may rise after 12 weeks of pregnancy and finally show a boy!

How BABYGRAM Can Offer the Most Reliable Baby Gender Prediction Online

BABYGRAM can give you a reliable prediction of your baby's gender. Experts at BABYGRAM use the nub theory to thoroughly analyze your ultrasound and prove 99 percent accurate results on your baby's gender.

What if you cannot see the Nub?

No worries, at BABYGRAM, we use a unique technology to compare your ultrasound with over 10,000 reference images to deduce the gender of your unborn baby. In Such cases, BABYGRAM has a track record of providing a reliable prediction of 85 percent accuracy from just nine weeks of pregnancy.

Our Artificial Intelligence algorithm, the foundation of the technology at BABYGRAM, is currently with reputable scientific journals. After a peer review, it will be up for publication in the coming future.

Are you excited about discovering your baby's gender? Learn more about our method, or order your ultrasound analysis now for just €15.90 !


Get now our FREE ULTIMATE GUIDE to master the Nub Theory

preview of the Ultimate guide to master the nub theory

The Empowering Aspect of Nub Theory

For many parents, the nub theory offers more than just a sneak peek into their baby's gender; it provides a unique opportunity for early bonding and preparation. Knowing the gender ahead of time allows families to personalize their preparations, from nursery decorations to choosing a name, thereby making the pregnancy experience more engaging and emotionally enriching. Additionally, for parents who have specific medical or psychological reasons for wanting to know the gender early on, the nub theory can offer valuable peace of mind. As we move into an era where personalized healthcare is becoming the norm, the nub theory stands as an example of how medical science can cater to individual needs and preferences, enhancing the overall experience of pregnancy in a meaningful way.

The Democratization of Gender Prediction through Nub Theory

One of the most compelling advantages of the nub theory is its accessibility. Unlike some other gender prediction methods that may require advanced imaging technology or invasive procedures, the nub theory relies on standard ultrasound images that are part of routine prenatal care. This makes it a more affordable and less risky option for a wide range of expectant parents. Furthermore, the rise of online platforms specializing in nub theory analysis means that even those without immediate access to specialized healthcare professionals can still benefit from this method. By democratizing access to early gender prediction, the nub theory serves as an equalizer, offering more families the joy and excitement of early gender discovery, regardless of their location or socioeconomic status.

What people say about us

Linda T.

Great service, had my answer in 2 hours, and you got it RIGHT ! First baby girl after 2 boys !! thanks !

Amber B.

Confirmed Girl and you knew it even if I was only 9 weeks pregnant. Congrats to your team !

Emily J.

Happy to finaly find a serious gender prediction service online ! I was about to order Ramzi theory but I read your article explaining it was all fake ! THANK YOU

Jennifer and Michael

So excited to get a glimpse on our baby's gender, we were really impatient to know and our obgyn wouldnt give us a clue, a huge thank you !

Nadia H.

Top service, answer received in 3 hours apparently it would be a little girl it's also what my doctor told me but I wanted to confirm too happy with this second opinion, I will keep you informed at the time of the scan of the 2nd trimester!

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A little boy for me, CONFIRMED at second scan ! Thanks for this service !

Mary F

You told me GIRL with 87% chance and your were right! A big Thank You to Stephanie from customer service she is so nice !

Patricia G.

At first I came here to use the chinese calendar predictor but you looked serious so I ordered an analysis. Result: confirmed boy at birth !

Carole K.

I am so happy with this service, I knew my grandchild's gender before my son and his wife who still dont want to know !

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You got him right at 8 weeks only, thank you !


I got a bit confused when uploading the pics but apart from that I recommend your service!


Got my result in an hour with the express delivery, thank you !


At last I got a girl, I am thrilled thank you !!

June & Jon

You got her right ♥

Chiara D

There was no nub visible on my photo so your service was the only way to know my baby's gender and YOU GOT HIM RIGHT !! This is impressive, I wish you good luck to develop this amazing service !

Violetta R

My husband was skeptical but you were right on my baby girl despite all other guesses, thank you !!

Dora L.

It did not work for me so I was refunded, a bit disappointed but I appreciate your honesty.

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