So it's sex length recessive. And what that basically means is we have an x uppercase B that basically describes the normal gene, and then we have the x lowercase B that describes the gene for that disease. Okay? 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.