I read an article (and subsequent study) which says that if your placenta is on the left, it's a girl and if it's on the right, it's a boy (almost 98% accurate supposedly). They also say that you can tell this as early as 5 weeks. Was this right for you? I'm curious if this is really a feasible way of gender prediction.
FYI: In a transvaginal ultrasound, left is left and right is right. However in a transabdominal ultrasound it would be the opposite, if you're wanting to take a look. Oh and the yolk sac is not the placenta (I had to google this myself, lol).