Which side of uterus is baby girl?

A baby’s gender is often detected via ultrasound around 20 weeks of pregnancy.
According to the theory, the placement of your developing placenta – which must be determined in a very precise way – can reveal your baby's sex. If your placenta is forming on the right side of your uterus, the baby is most likely a boy, the theory claims. If it's forming on the left side, it's probably a girl.
Dr. Saam Ramzi Ismali developed a theory (Ramzi’s method) that fetal sex could be determined as early as 6 weeks into pregnancy. The theory claims that the location of the placenta, or trophoblast, can define fetal gender as early as six weeks via ultrasound. If the placenta is developing on the left side, the sex is female. If it is developing on the right, the sex is male.

Unfortunately, Ramzi’s method has not been confirmed in any additional studies. There are no outward signs of sex until about 9 weeks of pregnancy. Differentiated genitalia cannot be seen clearly until about 15 weeks.2 As a result, many ob/gyns dismiss the validity of Ramzi’s method entirely.

A gender prediction method that has been studied, however, is the use of cell-free DNA. Researchers used cell-free fetal DNA in plasma of pregnant women to determine the early gender of the fetus with 96.7% accuracy.