Further to my article on NRO today regarding alternative sources of pluripotent stem cells, I wish to make clear, as I have in previous commentary on the subject, that I do not believe any method of stem -cell production is acceptable if it requires the procurement of oocytes from women by homonal stimulation (superovulation). It is a painful and potentially dangerous process, and employing it would almost certainly result in the exploitation of poor women, especially in underdeveloped parts of the world.