Since 1998 the volume of research being conducted using human embryonic stem hES cells has expanded primarily using private funds because of restrictions on the use of federal funds for such research. Given limited federal involvement privately funded hES cell resea... Lees meer.

In 2005 the National Academies released the report Guidelines for Human Embryonic Stem Cell Research which offered a common set of ethical standards for a field that due to the absence of comprehensive federal funding was lacking national standards for research. In... Lees meer.