In A Number, Caryl Churchill explores the human experience, the essence of personality, and nature versus nurture as a man confronts his father after discovering that he has several siblings - each one of his clones. Since the arrival of Dolly the sheep, the first mammal to be cloned, in the late-90s, the possibility of human cloning has sparked controversy. In recent years, with advances in genetic engineering, the practical and ethical issues regarding cloning continue to make headlines and incite lively debate. "We've got ninety-nine percent the same genes as any other person. We've got ninety per cent as a chimpanzee. We've got thirty percent the same as lettuce," says Michael Black in A Number. "Does that cheer you up at all? It makes me feel I belong."