Early in his administration, President Bush became personally interested in the issue of stem cell research. The Clinton administration had issued guidelines allowing the federal funding of research utilizing stem cells, and Bush decided to study the situation's ethics before issuing his own executive order on the issue. Evangelical religious groups argued that the research was immoral as it destroyed human embryos, while various advocacy groups touted the potential scientific advances afforded by stem cell research. In August 2001, Bush issued an executive order banning federal funding for research on new stem cell lines; the order allowed research on existing stem cell lines to continue. In July 2006, Bush used his first presidential veto on the Stem Cell Research Enhancement Act, which would have expanded federal funding of embryonic stem cell research. A similar bill was passed in both the House of Representatives and the Senate early in mid-2007 as part of House Speaker Nancy Pelosi's 100-Hour Plan, but was vetoed by Bush.