See the peer-reviewed study in the International Journal of Pregnancy and Childbirth (Int J Pregn & Chi Birth. 2019; 5(4):135-137). In a separate laboratory test from 2017, fetal sex was accurately determined in 99.6% of 241 pregnant women at 9 weeks gestational age and later into pregnancy.
https://www.amazon.com/SneakPeek-Early-Gender-Girl-Prediction/dp/B016201HCG

