So we took sperm cell number three and we combined it with a normal X cell as shown in this diagram. What would we form then? Well, we have two identical Y chromosomes, one X chromosome. So we form a Zygote that has an XY genotype distribution and that's what we mean by an XY carreotype. Now, it turns out that Zygotes with the XYY caraotype, the XXY genotype, the XYY genotype generally develop into fertile males and aside from being unusually tall and having extreme acne problems, they are generally normal. That is, they are ah, they are fertile and they can basically form offspring.