Sex matters: XIST and DDX3Y gene expression as a tool to determine fetal sex in human first trimester placenta

Abstract Fetal sex influences placental function as well as maternal and fetal health, being an important factor to consider in pregnancy studies. However, fetal sex determination in the first trimester of pregnancy still faces some technical limitations. Here we describe an RT-qPCR technique to determine fetal sex based on X-inactive specific transcript (XIST) and DEAD-Box helicase 3 Y-linked (DDX3Y) gene expression. This method is straightforward, reliable, fast and applicable on both, placental tissue and primary cells.