The nub theory is all to do with all that age-old guessing game of whether you're having a boy or girl. It is a concept that explores how a fetus's reproductive organs develop and not based around ...

Nub theory is a fun way to make a slightly-better-than-random guess at your baby’s sex after your 12-week ultrasound. (Hey, it’s probably more accurate than peeing in a cup of salt water to ...

Research conducted in 2012 indicates that even when ultrasounds are read by professionals, nub theory is only accurate about 30% of the time on fetuses less than 11 weeks’ gestation.

The nub usually develops around 11 to 13 weeks. According to the nub theory, the baby is a male if the nub points to an angle greater than 30 degrees against the spine.

The nub theory is basically about 'the angle of the dangle'. ... A scan at 12 weeks is around 75% accurate and at 13 weeks it's closer to 95% accurate. Advertisement.

Parents-to-be are asking strangers to guess their baby’s sex by posting scan pictures online, in a wacky new craze sweeping the internet.

The nub theory is based on predicting a child's gender at just 12 weeks Credit: Getty ... nub theory is only accurate about 30% of the time on fetuses less than 11 weeks’ gestation.