The House of the Scorpion by Nancy Farmer

Matt is six-years old, people call him a "filthy clone", but he doesn't know why, or what it means.
It is common for wealthy men of this time to have clones, whom they use to extend their lives with organ transplants. Most clones have their intelligence stunted at birth, but Matt, the clone of Matteo Alacran, does not. He lives the early years of his life on Alacran's (El Patron's) opium farm, where he faces prejudice and opposition. He has the courage to fight against his assigned fate, and shows that he is the same as any boy born of a human mother. This book chronicles the life of Matt and the struggles he faces being a clone.
This is a splendid book, with very likable characters. I recommend it to all teens.