The Ramzi theory was developed by a chap called, yes you guessed it, Dr. Saad Ramzi. The theory and research paper were published on ObGyn.net but the paper was never peer reviewed therefore, cannot be fully confirmed by other professionals.
The Ramzi theory suggests that the gender of a fetus can be seen as early as 6 weeks by looking at which side the placenta develops. According to the theory, if the placenta develops on the right you are likely to have a boy and if the placenta is on the Left then you are likely to have a girl.
During an ultrasound it can be quite difficult to see exactly where the placenta is forming at 6 weeks. During the development of the theory they used colour doppler to establish the site where the chorionic villi were forming. Without the use of colour doppler it would probably be more clear if the cord insertion is clearly visible. A specific view would need to be obtained to see this i.e. a transverse view which effectively shows a view as if looking through a cross section of the uterus from the top and when looking at the screen remember left is right and right is left. (just to confuse things, orientation is never what you think it is with ultrasound). With this view you can see which is left and which is right.
The Ramzi theory should be considered a bit of fun when looking at the gender of your baby and we certainly wouldn't recommend going our and spending money on outfits and nursery decor, simply because it is a theory and has not yet been proven or endorsed. We can only suggest that you take a look online and look at what mum's to be are saying, which in a lot of cases, the Ramzi theory has proven to be incorrect. At the same time, there is only a 50/50 chance of accuracy and we also don't know if the scans that they have undergone have used the correct views and have made accurate assessments of the placental location.