Bush's guardian of bioethics looks beyond stem cells.

Byline: Jeremy Manier and Ron Grossman

CHICAGO _ When President Bush asked Dr. Leon Kass last week to head a new council overseeing stem cell research, the University of Chicago professor accepted _ on the understanding that the council would also be a national forum for the even more vexing question of whether modern science has lost its moral bearings.

It's an issue Kass has been puzzling over his whole scholarly life. Thirty years ago, he greeted in-vitro fertilization by wondering if it amounted to "unethical experiments on the unborn."

House's attention, and made him one of the most influential counselors to Bush as he wrestled with the politically treacherous issue of federal funding for embryonic stem cell research.

A decisive moment in Bush's deliberations, according to aide Karen Hughes, was a July 9 meeting at the White House of Bush, Kass and another bioethicist. Hughes said their talk marked the first time Bush discussed in detail the ethics of permitting funding only for work on existing stem cell lines _ the compromise that he ultimately announced.

"I was invited," Kass said in an interview on Friday, "not so much to tell (Bush) what to do, but to help him think through the various moral issues."

He was, in fact, playing the role of the good professor, prodding a student to consider the…