it has nothing to do with abortions. they are left over from in-vitro fertilizations. if they aren't used for research, they are thrown away.
Would you advocate using the terminally ill for medical research that may hasten their deaths -- because, hey, they're gonna die anyway?
btw -- Clinton signed the bill forbidding federal funding for medical research involving the creation or destruction of human embryos. Bush was the one who lifted the ban for embryonic stem cell research, but only on the existing lines.