4 Ways to Determine the Gender on Ultrasound Scans

When it comes to determining gender on ultrasound scans, your best bet is to have a technician confirm. However, even professionals can get it wrong and we know of so many families who have been told one gender only to be completely surprised at birth.

If you can’t wait for the big surprise, here are some expert tips, tricks and theories for determining gender on ultrasound scans – from as early as 6 weeks too!

The Ramzi theory

This theory is based on Dr. Saam Ramzi’s ultrasonography research, which suggests you can determine gender on ultrasound scans as early as 6-8 weeks based on the placenta/chorionic villi location. It’s meant to be quite accurate.

Dr. Ramzi discovered that using the direction or orientation of the chorionic villi (future placenta) is an accurate marker in determining the sex of a baby.

If the placenta is forming on the right side – Male
If the placenta is forming on the left side – Female

If you are going for an early dating scan, you can ask the technician which side the placenta is forming on. You never know – it could be accurate!

The nub theory

The nub theory or, the angle of the dangle, is one way to determine gender on ultrasound scans before the 18-week anatomy scan. It can generally be done around the 12-15 week marker, but, remember, it’s not completely foolproof.

mum central — Source: Diagnostic Ultrasound

How it works: Before 15 weeks gestation, both males and females have genital tubercles, also known as a nub.

If the nub is angled greater than 30 degrees in relation to the spine, it is likely a boy.
If the nub is less than 30 degrees, straight out or down, it’s most likely a girl.

However, in order to determine this, the scan must be in profile view to allow viewing of the spine and the nub’s relationship to it.

The skull theory

The skull theory is a tricky one, especially for the untrained eye, but, basically, the theory suggests there you can tell the gender by identifying the shape, size, and other related factors of your baby’s skull while in the womb.

These factors can be seen in early ultrasounds, but, don’t be discouraged if you can figure it out on your baby’s ultrasound scan – all baby’s heads look the same to me too!

According to skull gender theory, gender experts can determine gender by the following criteria:

Cranial mass – The males are blockier and more massive compared to females, which are rounder and taper at the top.
Temporal Ridge – This runs along the outer side of the upper skull creating the square shape of the upper head and is more prominent in males than in females.
The ridge above the eyes (known as the supraorbital margin) – More prominent in females while males are round and dull.
Zygomatic bone (the cheekbone that lies under the lower eye ridge) – More pronounced on the male skull.
The Mandible (lower jaw) bone – Females are rounded, and males are squared.
The superciliary arch – Larger and more pronounced in males.
Gonion (the most posterior inferior point on the angle of the mandible) – More flared and sharply angled in males.
Teeth – Males tend to be larger.

The potty shot

The potty shot refers to the picture of the baby from the bottom up. It gives a clear view of bub’s legs and what’s in between them and is usually performed as part of the 18-week anatomy scan.

Here’s what to look for:

Female: A girl’s parts will look like three lines between the leg, what is known as the “hamburger sign”. The labia would be associated with the bun and the clitoris would resemble the hamburger patty.
Male: The male genitalia looks more like a hot dog. At a 20 week scan, and with the right potty shot, it’s quite clear to see the difference but keep in mind that sometimes the female labia can be mistaken for the male genatalia.

So there you have it – how to determine the gender on ultrasound scans. If you’re looking for more ways to guess the gender, check out:

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