The 2010 bestseller The Immortal Life of Henrietta Lacks highlighted ethical controversies surrounding scientists' use of HeLa cells. The cells are descended from a tumor taken without consent from Henrietta Lacks, a poor black woman who died in 1951. Ethical concerns resurfaced with the publication of the HeLa cell's genome. The National Institutes of Health has now issued guidelines. For an explanation, Linda Wertheimer talks to NIH director Francis Collins.