Why does a human male determine the sex of the child?

Answer

Wiki User
05/31/2009

Because the male carries one X and one Y chromosome, whereas a female carries two X chromosomes. Therefore, all female gametes (eggs) will contain an X chromosome, whereas male gametes (sperm) will contain either the X or the Y chromosome.

When one sperm fuses with one egg, it will either be XY (male) or XX (female), depending on which of the male's sperm, the one with the X or the one with the Y, made it there first.