The Nub theory analyzes the angle of the genital tubercle (the "nub") visible in your ultrasound to predict your baby's gender. Our most requested analysis method, best between 11-14 weeks.
The Nub theory (also called the "angle of the dangle") is one of the most popular methods for early gender prediction. It examines the genital tubercle — a small protrusion visible between the baby's legs in ultrasound images taken between 11-14 weeks.
The theory is based on the observation that this nub develops at different angles depending on the baby's gender. Our trained specialists carefully measure the angle relative to the baby's spine to provide their prediction.
Submit your 11-14 week ultrasound where the genital tubercle is visible between the baby's legs.
Our analysts locate and identify the genital tubercle in your ultrasound image.
We measure the angle of the nub relative to the spine to determine the gender prediction.
Receive a detailed report with prediction, confidence level, and analysis notes via email.
Want to understand how a nub theory prediction works before booking? Here are examples of what our analysts look for when reading an ultrasound:
The genital tubercle angles upward more than 30 degrees from the horizontal line of the baby's spine. This steeper angle is consistent with male development. At 12+ weeks, this sign becomes more pronounced and easier to read.
The genital tubercle lies parallel or slightly angled downward relative to the spine. A nub that points less than 10 degrees upward or runs parallel is typically associated with female development. The nub may also appear shorter.
While these free examples help you understand the theory, a professional analysis considers image quality, baby position, gestational age, and multiple reference points. Our trained specialists provide a detailed report with confidence level for every prediction.
The Nub theory is based on how the genital tubercle develops differently in male and female fetuses:
Note: This theory is based on anecdotal observations and has not been scientifically validated.
Upload your 12-week ultrasound and let our experts provide a professional gender prediction using the Nub method. For the most confident result, combine it with Ramzi or Skull theory.
Upload Your ScanAnalyzes placenta position during early pregnancy. Most effective between 6-12 weeks for the earliest possible prediction.
Learn about Ramzi TheoryExamines cranial shape characteristics from ultrasound images. Best combined with Nub theory for a complete analysis.
Learn about Skull TheoryCommon questions about the Nub theory and gender prediction.
Medical Disclaimer: The Nub theory is based on anecdotal observations and has not been scientifically validated. Our predictions are for informational and entertainment purposes only. Always consult your healthcare provider.
