My daughters and I had heard that the book was very different from the movie, and since we usually prefer the books, we all read the book before seeing the movie. As expected, the book is amazing and much more complex and emotional than the movie. We will not spoil it for you by avoiding the endings of both the movie and book (which are very different), but here are our reviews.
My Sister's Keeper (2004) by Jodi Picoult is the story of a young girl who was genetically engineered and even born to help save her older sister from an extremely rare disease requiring cells, bone marrow, and even a kidney transplant. While that drama is unfolding, their mother (Cameron Diaz) is hell-bent on not losing a child, their dad (Jason Patric) is struggling to "do the right thing," and their brother is ignored, getting arrested, starting fires, using drugs and alcohol, and driving crazy. Add a lawyer with a life-threatening disease, a guardian who is in love with said lawyer, and the book becomes a serious page-turner, especially in the last few pages!
The movie, My Sister's Keeper (2009), on the other hand, is not as good as the book, but is about the same family going through these extremely tough times. It focuses on the youngest sister suing her parents for the right to her own body which includes the right to say "no" to a kidney transplant even though refusing the transplant will kill her sister. The brother is not a out-of-control, there is less drama around the lawyer, and well the end just leaves you yelling at movie-makers who mess up great stories!