Actually he said that depending on which of the mothers genes cross over and exactly how they twist and exchange that they can be normal XY (in which a twist and change has occoured where both the orange and black genes exist on the same X chromosome) but it's even more rare than the XXY. He went through all the science about it and it was very complicated, interesting but complicated.Originally Posted by valanhb
Yup, they are out there but are very rare. They have to have XXY chromosomes, because the black and orange (or grey and tan) are held on separate X chromosomes, and obviously to be a boy they need the Y. That's also why they are almost always sterile.