AFAIK, there is no outright ban in the US on ESCR (else the current budget wouldn't have funding for ESCR). The controversy is over federal funding; current policy is to fund ESCR only on preexisting stem cell lines, while militant pro-ESCR advocates want unlimited federal funding of ESCR. As sources of additional stem cell lines include aborted fetuses and viable (but non-implanted) in vitro embryos fertilized in pursuit of fertility treatments, the issue has become a proxy for the abortion debate.