From Muhammad ibn 'Uthman Adh-Dhahabi's "Al-Kabar" (The Major Sins) [p.117]
Our righteous forefathers took special precautions against mixing socially with handsome boys, considering them to be a greater temptation than women. Some scholars go to the extent of prohibiting a man to be alone with a young boy in a house or a bathhouse, on the analogy of the prohibition of being in privacy with a strange (non-Mahrem) woman. The Prophet (SAW) said: "When a man is in privacy with a woman, Satan joins them as the third." Now, if there is a beardless youth who is more beautiful than a woman, the temptation from him in privacy may be greater than a woman's, as the evil of homosexuality is definitely much greater than the evil of zina with a woman.
Sufyan Thawri once entered a bathhouse and then a handsome boy came in. Sufyan called out: "Please take him away from me, for if there is one Satan present when one is in privacy with a woman, there are fifteen Satans present when one is in privacy with a beautiful boy."
Says a lot about Sufyan Thawri eh?
Other major sins, if anyone's interested, include such hideous depravity as a slave running away from his master [the 57th major sin], being a cuckhold [the 34th], a woman's bad conduct to her husband (of course) [47th], gambling, backgammon and chess [the 20th]. Murder is the second major sin (after associating anything with Allah) but rape and paedophilia aren't mentioned - most probably because such things didn't exist 1400 years ago.