Credit: Andrew Nagata

William Hurlbut, a physician and ethicist, is best known as a member of the President's Council on Bioethics. Though he has spoken out against the destruction of embryos for research purposes, he is nonetheless a supporter of ­embryonic-stem-cell research. He avoids what would otherwise be a terminal para­dox through a proposal that he calls "altered nuclear transfer," or ANT. His goal: to create embryonic stem cells without destroying human embryos.

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