Learn more about early gender determination theories that are applied using ultrasound scans. Following these guides will help you or one of our experts to apply the theories as accurately as possible.
Submit your scan to us as early as 6 weeks for Ramzi Theory, and as early as 12 weeks for the Nub and Skull Theories.
Ramzi Theory
Dr. Ramzi conducted a peer-review study to prove that sex may be determined earlier than 20 weeks. Ramzi Theory is 97% accurate when scanned in person. It uses chorionic villi (future placenta) placement and orientation to determine the sex of your baby.
This article covers Dr. Ramzi’s ultrasonography Research to explain how to use this method when you go to your first ultrasound when you are around 6-8 weeks pregnant.
Learn what the chorionic villus is and how to find it on your ultrasound scan. Additionally, identify where the the right and left side of your uterus while looking at your sonogram. Take our Ramzi Theory quiz to test your knowledge! read more
Nub Theory
The Nub Theory is one of the most accurate early gender predictors both in person and analyzing using a static image. The Nub Theory uses the “angle of the dangle” to determine whether the baby is a boy or girl. The nub begins to change around 11 weeks, but analysis of the nub angle is most accurate beginning at 12 weeks through 14 weeks gestation. Learn the timeline and characteristics of the genital tubercle in our Nub Theory Guide. read more
Skull Theory
Use our Skull Theory Gender Prediction Guide to learn about the marked differences between male and female skulls. Using anthropologists’ discoveries about skull shape and size differences, our experts explain the details using ultrasound scan photo examples to illustrate. Read about the history, accuracy and application of this information. Take our Skull Theory Quiz to predict the sex of your baby using the Skull Theory. read more
20-week Anatomy Scan- Level 2 Ultrasound
What should you expect at your 20-week anatomy scan? Learn what your doctor or ultrasound technician is looking for and measuring during this routine exam. Find out how to spot the differences between boy and girl parts at this stage. View our technician-illustrated confirmed boy and girl ultrasound scans for 20 weeks gestation. read more