Cell-free fetal DNA (cffDNA) sex determination is a non-invasive method used to determine the sex of a fetus by analyzing the fetal DNA present in the mother's blood. The cffDNA circulates in the maternal bloodstream during pregnancy, typically after the 7th week. By detecting the presence of Y-chromosome material in the blood, it can confirm a male fetus, as females lack a Y chromosome. This test offers a reliable and early option for sex determination compared to traditional methods like ultrasound. It is often used in conjunction with non-invasive prenatal testing (NIPT) for screening genetic conditions. The test is highly accurate, with a very low risk of false results. It poses no risk to the fetus and is considered a safe alternative to invasive procedures.