I'm going to agree with the majority opinion, here:
Chapter 5, "Lavender": In which Genji is a SKAAAAAAAAAAANK!! (tm telophase).
Genji is sick, goes to the mountains to recover, sees a ten year old girl who looks just like his step-mother (who looks just like his dead mother), and in fact turns out to be his step-mother's niece, decides he has to have her. Everyone around her says, "Dude, come back when she's hit puberty," despite his claims that he doesn't want her for improper purposes—apparently they weren't very convincing claims.
He ends up kidnapping her the night before she's supposed to go to her father's house, so her father doesn't have any idea where she went, and starts brainwashing her in the finest domestic-violence fashion:
"You are not to sulk, now, and make me unhappy. Would I have done all this for you if I were not a nice man? Young ladies should do as they are told." And so the lessons began.
Loiosh: "Can I eat him now, boss, huh?"
You know it's a bad chapter when the news that Genji has possibly impregnated his step-mother off-screen is almost an afterthought. (My cast of characters states that the resulting child (or, I suppose, a resulting child) is Genji's, but the characters don't know yet.)
Ugh. Ugh. Ugh. I wanted to scrub my brain out with a wire brush after this chapter. I believe he's not actually having sex with the ten-year-old (who is called Murasaki, but telophase indicates the author's name stems from the character's, not the other way around), but he's going to, and ugh.
Like rachelmanija, I was also surprised and relieved that the general "Genji is Perfect" (G=P) belief of the other characters didn't extend to his intentions to the young girl; I just wish the same was true of the author's attitude.
If I were reading this alone, I would probably stop now. Because we've been reading together and it is fun to hear the collective yells of "SKAAAAAAAAAAANK!!" echo around the Internet, I'll probably keep going—just how low can Genji go? Tell me this is the lowest, please? (I mean, it's not much comfort, since this low point will permeate the entire rest of the book, but maybe there won't be any more low points?)