From what I believe, 50%. The chromosome from the father can either be X or Y, so it’s a chance to carry it in the X gene if the child is a girl. If its a boy, then it has no chance of carrying the gene. Hope this helps
Gregor Mendel, in full Gregor Johann Mendel, original name (until 1843) Johann Mendel, (born July 22, 1822, Heinzendorf, Silesia, Austrian Empire [now Hynčice, Czech Republic]—died January 6, 1884, Brünn, Austria-Hungary [now Brno, Czech Republic]), botanist, teacher, and Augustinian prelate, the first person to lay the mathematical foundation of the science of genetics, in what came to be called Mendelism.
