how did rouge get the white stripe? did it come with her powers? or..

Comic and cartoon wise she always had it. But movie wise she got it por absorbing to much of magneto's powers.

the magnet grandpa caused it.check the 1st movie

It is a result of her mutation.. but the movie changed it =/

go to the first movie they have to save rogue from magneto and they throw wolverine and whil shes in the machine she gets it right before wolverine saves her