So if this were true, if it is sex link recessive, then what that means is this female individual must be x lowercase b, x lowercase B and this individual, because it's a male and it's normal, that means we must have x uppercase B and y. So let's actually carry out the following crossing process between these two individuals and let's discuss what the distribution is of the genotypes of the offspring produce. And let's see if that's consistent with information given to us in this pedigree. So remember, this is generation one, these are the individuals of generation two, and these are the individuals of generation three. So we have, this individual produces either this sperm cell or this sperm cell. This produces only one type of xcel, x lowercase B.