4. A Right Boob
Breast size is another, 100% foolproof method of telling the sex of your baby. Apparently, if your right breast is larger, then it's a boy. The problem with this, aside from its stupidity, is that most women have breasts of uneven size anyway. Personally, I think that if you rely on the size of your breasts to tell you that you're expecting a boy, then that´s definitely a right boob.