Malcolm Parker is right to insist that the ethical issue at the heart of the debate about embryonic stem cells concerns moral status of a human embryo. Is it, or is it not, an entity to whom we owe the kind of respect that excludes deliberately destroying it? And he is right that both 'sides' to the debate sometimes obfuscate that issue. If a human embryo is the kind of entity that is a limit to our will, then discussions about the relative therapeutic potential of adult v embryonic stem cells cannot reasonably arise. So his frustration with both 'sides' is understandable