It's in the FAQ of ultrasound gender prediction forum.
link is : http://www.in-gender.com/cs/forums/t/43154.aspx
The Placenta Theory?
There is a theory about placental
attachments and the gender of the baby. As the theory goes, if the
placenta is on the LEFT, then its a girl. If it is on the RIGHT, it is a
boy. I find this theory is often correct, but then again, I am scanning
the patient at 18+ weeks, and can see the placenta clearly, as well as
the gender. The theory that uses the placenta studies the use of colour
doppler to identify the placenta at 6-7 wks. Personally, I would not
chance exposing a teeny tiny developing embryo to the high levels of
sound waves that is used for colour doppler. Just a whole risk vs
benefit thing. Without colour, the placenta is tough to identify
accurately this early on. 12 wks would be more reasonable.
Posting a picture of the baby and asking where the
placenta is not accurate here unfortunately. The tech who took your
image, did it from an angle that best shows the baby or nuchal fold or
so forth. She has to take the pic with the probe sideways, or up and
down, or obliqued to get this "angle". Sadly, if the angle of the probe
is not documented on the image, it is impossible to guess where it
"actually" is. To be honest, sometimes the tech does not think of this
probe angle, she is just interested in getting the best shot possible of