Because a female's<span> eggs only contain X </span>chromosomes<span>, the </span>chromosome<span> found in the male's sperm decides the </span>sex<span> of the </span>embryo. There are only two possiblecombinations<span>, XX or XY. An </span>embryo<span> with the XX genotype is a </span>female<span>, while the XY genotype </span>produces<span> a male.
