when did you become genetically male or female
Sexual differentiation in humans A babyâ€™s sex is determined at the time of conception. When the baby is conceived, a chromosome from the sperm cell, either X or Y, fuses with the X chromosome in the egg cell, determining whether the baby will be female (XX) or male (XY).[5] To be female, one needs to be (XX), whereas to be a male, (XY) is needed. It is the Y chromosome that is essential for the development of the male reproductive organs, and with no Y chromosome, an embryo will develop into a female. This is because of the presence of the sex determining region of the Y chromosome, also known as the SRY gene.[6]