The following July, the National Institute of Health came out with its guidelines on appropriate stem cell sources. Embryos must be "derived from an embryo that was created for reproductive purposes and was no longer needed" and was donated for scientific purposes.
Because under these guidelines federally funded projects could obtain stem cells from private institutions that continue to use extra, donated embryos from in vitro fertilization to produce stem cells for research, critics of Obama's order argue that it is using federal money to support the destruction of life.
Scientists argue that Obama's order is not so different than what existed before, only that instead of sanctioning those lines created as of 2001, it sanctions those lines that are already created since then.
"If having federally funded research that uses privately created stem cell lines misinterprets the Dickey-Wicker amendment, then congress had nine years during the Bush administration to say it was being misinterpreted. Obama's interpretation is the same as Bush's," says Dr. Robert Klitzman, director of the Masters of Bioethics Program at Columbia University.
MedPage Today's Emily Walker contributed on this report.