AP BIOLOGY

Detailed explanation-1: -Every egg has an X sex chromosome; a sperm can have either an X or a Y sex chromosome. If the sperm that fertilizes an egg has an X chromosome, the baby is female; if it has a Y chromosome, the baby will be a boy.

Detailed explanation-2: -The two sex chromosomes in the egg and sperm are what determine whether you’ll have a boy or girl. Eggs always have an X chromosome, and sperm have either an X or Y chromosome. Whichever sperm is the winner will penetrate and fertilize the egg, creating either an XX (girl) or XY (boy) pair.

Detailed explanation-3: -Short of medically implanting an embryo that is known to be a boy, there are no guarantees when it comes to the sex of your baby. In general there is approximately a 50/50 chance of having a boy or girl if things are left to nature. It all comes down to which sperm wins the race, and millions of them are racing.