Gender Theories

There are many baby gender theories circulating the web, however many have little or no proven studies to suggest they are anything other than old wives tales,  the following theories are what can be used to predict your babies gender from your ultrasound scan.


The Ramzi Theory

The Ramzi Theory also known as Ramzi’s method was based on the theory of using the placenta/ chorionic villi location as a marker for  gender determination.

The study was conducted by Dr. Saam Ramzi Ismail using ultrasound scans between 6-8 weeks, 6 weeks being highly reliable.

The method correctly predicts the foetus gender in 97.2% of males and 97.5% of females early in the first trimester.

Ramzi Method: 6 – 8 week gestation scan accepted

The Full Ramzi Study can be found here.


The Nub Theory

The more popular theory: Nub Theory,  Before 15 weeks gestation both male and females have genital tubercles which appear to be identical, however there is a notable difference to the position of the nub often referred to as the ‘Angle of The Dangle’.

Determining gender with the use of this method has proven highly accurate.

Ultrasound scans between 12-15 weeks with a profile view can be analysed by the angle and shape of the nub.

​Below are two scan images the first being female and the second being male. The scan must be in profile view, to allow viewing of the spine, and the nub’s relationship to it.

The Skull Theory

Although many use this theory as a prediction to their baby gender we also look at other factors to determine the gender of the baby, such as using the nub theory. The Skull Theory although very popular and can be used as a gender prediction, however their is no scientific evidence to prove its accuracy even though many claim it to be 92% accurate.



A. The mans cranial mass is more blocky and massive compared to the females which is rounder and tapers at the top.

B. Temporal Ridge – runs along the outer side of the upper skull creating the square shaped of the upper head. More prominent in men than women.

C. A woman’s supraorbital margin (the ridge above the eyes) is sharper, while the males is rather round and dull.

D. The Zygomatic bone (the cheekbone that lies under the lower eye ridge) is more pronounced on the male skull.

E. The Mandible (lower jaw) bone of a woman is rounded, while the male’s is squared.

F. Frontal bone forehead structure terminates at the brow. The male forehead is lower and more slopping.

G. Men have a deeper cranial mass.

H. The superciliary arch is large and pronounced in the man.

I. A males gonion (most posterior inferior point on angle of mandible) is more flared out and sharply angled.

J. The teeth of men tend to be larger

More information can be found Here.

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