From the 8th week of gestation, we can determine the sex of a baby. It is a simple test, without risks and 99% reliable.
In previous decades, we had to wait until week 15 of pregnancy to be able to know the sex of the baby through an ultrasound and even then, it was not sure.
Today you can tell the sex of your baby with a simple blood test of the mother, where the child’s genetic material is contained as well, which is known as free fetal DNA. The analysis consists of the detection of DNA sequences.
In case of twin pregnancies, the effectiveness of this test decreases.