Unity is God's will) for gays and straights. Complementarity is a conclusion, not an argument. If you quit thinking of gay sex as icky, it will start to click. The institute for marriage tried that argument in Perry and it was not coherent to anyone who heard it. This issue is settled civilly and resistence to it from the Church will be ended from within by gay couples, their families and gay priests and bishops. There is ample justification for when they make their move to do so, just as clerical celibacy and a male priesthood will also fall.