What do you think about adults reading books written for children?

What do you think about adults reading books written for children?

It seems to be a common occurrence these days for authors to try to cross over from writing for one age group into either a more adult or a more juvenile market. Ann Brashares (author of the teen novel The Sisterhood of the Traveling Pants) has made news recently by writing her first adult novel. Author and scientist Steven Hawking has announced that he will be writing a children's novel. James Patterson has written an excellent young adult series: Maximum Ride.Will adults who admire Hawking pick up his children's book just because he wrote it? Will teens who like Brashares happily read her book meant for an older audience. Should age matter? As an adult, do you happily read books targeted to teens or even to children, or would you be highly embarrassed to be seen carrying around a "juvenile" title? As a teen or younger reader, do you like to read "adult" books, or are you happy with the book marketed for your age group? Please share your thoughts below.
As for myself, I will happily read just about anything. I read teen or children's books often. I particularly have enjoyed some of the fantasy books marketed to the teen audience--like Patricia's Wrede's Dealing with Dragons and Garth Nix's Abhorsen series. A good book is a good book, no matter who it's written for.

sue