Iggrot Moshe, Yoreh De'ah 3:115

When the manuscript was sent to me by Rabbi Daniel, I saw in it another matter. The wicked had intended to weaken the prohibition of male homosexual intercourse, first by the question of why the Torah had prohibited it. In itself this is a great evil that weakens the prohibition for the wicked ones who have this ugly craving, which is so detestable that even the nations of the world know that there are no abominations like it. It needs no reason since it is an abomination, despised by all the world. All understand that transgressors of this sin are corrupt and not members of civilization at all. And when the reason is sought for this prohibition, the asking of such a question removes [from the prohibition] all the obscenity, shame, and disgrace, and completely disparages it. Moreover, his rationale [for the prohibition] is to ensure that men marry women and fulfill the commandment to reproduce [be fruitful and multiply]. This explanation only further weakens the prohibition. It is as if he is saying that there is no sexual prohibition at all except as a support to the positive command to reproduce, which is not considered a very serious matter by the world. It is prohibited to publish this, just as if it were heresy, since it reads a Torah text in a fashion contrary to the Halakha. Because errors like this in other places in the book can be found and because there is no one who can read through the book carefully from the beginning to the end [to remove such material], it is prohibited to publish even one word from it, according to my opinion. [Translation by Rabbi Steven Greenberg]