The baby gets an X chromosome from its mother and either an X or a Y from its father. If the sperm carries an X then the baby will be a girl (XX); if it contains a Y then a boy will be born (XY). The father’s chromosomes, therefore, determine the sex of the baby.
The baby gets an X chromosome from its mother and either an X or a Y from its father. If the sperm carries an X then the baby will be a girl (XX); if it contains a Y then a boy will be born (XY). The father’s chromosomes, therefore, determine the sex of the baby.