I read this JKR interview on Time here
Okay, there is this part that goes:
Rowling has never finished The Lord of the Rings. There's something about Lewis' sentimentality about children that gets on her nerves. "There comes a point where Susan, who was the older girl, is lost to Narnia because she becomes interested in lipstick. She's become irreligious basically because she found sex," Rowling says. "I have a big problem with that."
Now I have read the Chronicles and I'm very sure that Susan wasn't lost to Narnia because of sex but because of vanity. Let's not forget that one of the 7 books featured a very Ron/Hermionish pair of children that and I quote 'were so used to arguing and making up again that when they grew up, they got marreid so as to continue to doing it more conveniently.' Or that Prince Caspian of 3 stories, met and wooed a lady in one of his adventures and had a son. I greatly doubt that CS Lewis ever had anything against sex. It just wasn't necessary to emphasize it in the context of what he was writing.
Frankly, those casual condescending statements of Ms Rowling towards Toklien and Lewis grated badly. The whole idea of noble, superior centaurs was created in the forests of Narnia. And let's not talk too much about the odd parallels between LotR and HP. http://www.mugglenet.com/funlists/hpvslotr.shtml
Let's not talk about the fact that it was Tolkien's great works and the efforts it costed him that gave 'fantasy' the authenticity it now enjoys as a serious genre - the authenticity the likes of Rowling take for granted.
Maybe it's the fame, maybe it's the fortune. Maybe I'm reading too much into it at all. But it seems like Rowling doesn't just rank herself up there with the greats, she happens to think that she surpasses them.