Some also believe such tissues are ethically tainted. As an alternative to such studies, Bush has said he supports research using fetal tissues retrieved from spontaneous abortions. That's a position endorsed by the Roman Catholic church. We're against the research establishment having to collaborate with the abortion industry. Bush has also said he supports research on other kinds of stem cells, which can be obtained from adults instead of from embryos or fetuses.
Recent studies suggest that adult stem cells have great therapeutic potential.
But because no one knows whether they will prove as useful as embryonic or fetal cells, many researchers favor pursuing both routes simultaneously. Administration spokesmen Ari Fleischer and Scott McClellan have declined repeatedly in recent days to clarify what policy changes, if any, the administration intends to make other than to reiterate Bush's past comments. Speaking on background, some representatives of patients' groups have said in recent days that they are fearful of pressing the point in the hope that administration officials are still familiarizing themselves with the issue. More than 135 NIH-funded projects rely specifically on fetal tissues, and many more are believed to use those tissues incidentally. Another project uses human fetal brain cells to understand the molecular mechanisms that underlie multiple sclerosis.