For the last 50 years, Dr Shettles has been considered the most influential fertility expert and the father of IVF. “How to Choose the Sex of Your Baby” is his influential book that made him famous.
This doctor’s theory is based on the differences between X (girl) and Y (boy) sperm, which is said to have a 75% success rate in aiding couples to conceive a baby of the desired sex. However, there is little official research that can prove this.
His theory on conception works on the principle that Y sperm are smaller and faster than their X counterparts but are also more fragile. On the other hand, X sperm are seen as larger and slower, but more flexible and able to survive for a longer period.