Anti-abortion Democrats are "holding firm," said Rep. Bart Stupak, D-Mich., the group's leader, reitereated Friday--and that's worrisome news for party leaders who badly need their votes.

"I want to pass health care, but there's a principle we do not want to cross," Stupak said on ABC's "Good Morning America."

The House of Representatives Sunday plans to consider health care legislation passed Dec. 24 by the Senate, which contains less restrictive langauge on abortion than the bill approved by the House Nov. 7. It's highly unlikely that language will change.

If the Senate bill is approved by the House, members would consider a second package of changes to the bill. But that is also unlikely to have any abortion measure.

Stupak suggested the political remedy could be other legislation, saying "That's one may, maybe. But we still have to deal with the Senate."

Democrats need 216 votes to pass legislation Sunday. While the party controls 253 of the currently-filled 431 seats, 39 Democrats voted no in November. Stupak estimates about a dozen colleagues share his concern about abortion.