Prevalence of methicillin-resistant Staphylococci species isolated ... by Boa, Tyler T.; Rahube, Teddie O.; Fremaux, Bastien; Levett, Paul N.; Yost, Christopher K. / Journal of Environmental Health.
The X and Y chromosomes, also known as the sex chromosomes, determine the biological sex of an individual: females inherit an X chromosome from the father for a XX genotype, while males inherit a Y chromosome from the father for a XY genotype (mothers only pass on X chromosomes).
Sperm cells carry either an X or Y sex chromosome. Female gametes or eggs, however, contain only the X sex chromosome and are homogametic. The sperm cell determines the sex of an individual in this case. If a sperm cell containing an X chromosome fertilizes an egg, the resulting zygote will be XX or female.