Can a male have the same X chromosome as his paternal grandfather?

Answer 1

No, he cannot.

He cannot even have the same X chromosome as his father.

The reason is that a male has an X and a Y chromosome in his genome. The Y must come from Dad, because Mum does not have any Y to pass on!

So the X must come from Mum.

Now looking at grandparents: a male's father supplied the Y, and father's Y came from the paternal grandfather. So the paternal grandfather's contribution must be the Y chromosome.

The male's Mum has two X chromosomes, one from the maternal grandfather, and one from Mum's Mum.

Answer 2

Yes, it is possible for a male to inherit the same X chromosome from his paternal grandfather. This can happen if the X chromosome is passed down unchanged from the grandfather to the father, and then from the father to the son. This would result in the male having the same X chromosome as his paternal grandfather.