Apparently so according to John Byrne over at his website:
http://www.byrnerobotics.com/forum/f...065&PN=1&TPN=2

Incidentally, despite what others -- including later writers of the characters -- may have read into my text, I had no intention that Jean-Marie and Jean-Paul have an incestuous relationship. He was Gay, and the girls offered no allure. What I was trying to play -- subtly, because of Shooter and the Code -- was his attraction to Walt, and his jealousy of Aurora for doing what Northstar could not.