[28] Now at that time a certain bhikkhu, oppressed by discontent (anabhirati), cut off his own genital organ (aṅgajāta). … They reported this matter to the Blessed One. … "Bhikkhus, when there was one thing that ought to be cut off, that foolish man (moghapurisa) cut off another. Bhikkhus, one's own genital organ is not to be cut off. Whoever should cut it off commits an offense of grave transgression (thullaccaya)."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.