Begetting children is not a requirement for a canon law marriage.  Willingness is, but it is impotence, not sterility, that is the bar.  The term cry to heaven for vengeance is sloganeering, not doctrine and it applies to pederasty, not consensual sodomy.  Cry all you want, at some point natural law rears its head and says that gays were born that way due to epigenesis in the womb and that they have every right to sexual expression that any human has.  Ratzinger's opinion on the made up natural order notwithstanding.