Originally Posted by Canemacar
While the identity of the Third Summers Brother had been a mystery for nearly a decade, the descision to deal with it once and for all(again), was probably sparked by Claremont making Gambit the third summers brother in X-men: The End.
But really, by Sinister using Scott's DNA, that means Remy would be more of a son and less of a brother. I mean, Corsair had nothing to do with it. It was a blending of Scott's DNA with Sinister's own.