Determining Sex: What determines a child's sex? Usually it is the sex chromosomes in which two X chromosomes in the nucleus of its original egg cell and it will become a female; a Y and an X chromosome and it will become a male. An egg will have at least one female determining X chromosome. A sperm cell, however, may contain either an X chromosome or a Y chromosome. If the fertilizing sperm cell contains …showed first 75 words of 582 total…

…showed last 75 words of 582 total…this area will become the lips of the vagina. Then in the tenth week, the primary sex cords continue to disappear, while the cortical cords continue to extend and grow larger. As they do so, they incorporate the primitive germ cells that earlier migrated from the yolk sac. The Mullerian ducts continue to grow. Later, they will differentiate into the uterus, the upper vagina and the oviducts, which will connect the ovaries to the uterus.