On July 25, 1997, researchers from Johns Hopkins University announced, at an international symposium on the ethics of human cloning and stem cells, that they had cultured human stem cells in their lab, using tissue taken from aborted human embryos. (Stem cells are the basic, unspecialized cells from which all other cells develop.) The researchers made the announcement before their research was published because they wanted to spark discussion that would establish guidelines for the ethical use of embryonic stem cells--a discussion that continues today.