Not always. It just depends on if the traits stay the same
there would be a 50 50 chance for the child to have it depending on the genes on the grandparents
Sleet
Might be wrong lol sorry if it is
This can happen because you have recessive and dominant characteristics passed down. So you can get a totally different chromosome that doesn't come from your parents because your grandparents may have had it or great grand parents, the line keeps going .