Leon Kass argues against cloning of humans and human embryos. He draws upon the Aristotelian notion of self-realization and contends that humans are essentially social. Our social nature depends upon our social kinships. The liberal value of reproductive freedom can support parents in doing whatever they want. It groups helping a childless couple to have a child with helping a parent to produce a clone or, even, a “perfect baby.” The repugnance of eugenics enters at this point to support a ban on human cloning.