This is the last part of a five-part series on health care reform

Middle ground is hard to come by on the issue of abortion, and the health care debate is no exception. 

The House and Senate, entering what may be the final weeks of health care talks, are still struggling to come up with a compromise that will settle disagreements over how best to ensure public dollars do not go toward funding abortion coverage. 

The bills in both chambers are distinctly different when it comes to abortion funding. The House sets up a veritable brick wall between taxpayer funds and abortion providers. The Senate, critics say, provides too many openings for public money to fund abortion. 

"There's either funding for abortions or there isn't," said Charmaine Yoest, president of Americans United for Life. "There really isn't a middle ground on the issue." 

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A big problem in resolving the dispute is that the Senate is already on record opposing the kind of strict provisions that House Speaker Nancy Pelosi needed in her bill in order for it to pass. 

Pelosi, an abortion rights supporter, was only able to pass a health care bill after allowing a vote on tough abortion language sponsored by Michigan Democratic Rep. Bart Stupak

The move won her 40 Democratic votes she easily could have lost if the restrictions had not been included. Even with them, the House bill only passed by five votes, leaving little room for compromise. 

Yet anti-abortion forces in the House are not happy with the Senate bill, which has looser restrictions. The package would require that insurance companies segregate any federal subsidies so that only private funds from customers are used for abortion coverage. It would also have companies charge a specific fee dedicated for abortion coverage, which has angered some groups. 

In addition, at least one plan in the state-by-state insurance exchanges would have to offer abortion coverage, unless a state individually opts out -- which isn't easy. 

"Each state, if they want out of the abortion mandates that are in the Senate plan, would have to pass their own laws to get out of funding abortion," Yoest said. 

Abortion-rights supporters in the Senate, which helped defeat a Stupak-style provision before the full chamber voted on health care in December, are determined not to let the House language leak into their bill. 

But will House members who voted for the Stupak amendment accept anything less? 

Rep. Jason Altmire, D-Pa., suggested moderates would be insistent. 

"The exclusion has to remain in place -- no taxpayers dollars can be used to fund abortions," he said. 

The question is whether the House and Senate can find some middle ground that won't lose votes from one group or the other. 

House Democrats who voted for the Stupak amendment concede the Senate won't accept that specific language. 

"We know what can and cannot be done in the Senate, so the question is can we come up with other language that will be acceptable to uphold the status quo?" said Rep. Henry Cuellar, D-Texas. 

Analysts say some of the Democrats who supported the Stupak provision would consider other language, depending on the rest of the bill. 

"Not all of them are going to be Stupak or bust," said Jim Kessler, vice president for policy with Third Way. "A lot of the folks ... they wanted to see to make sure that there wasn't an expansion of abortion coverage, and they'd certainly be willing to take a compromise." 

But Kessler said there may be 10 to 15 House Democrats that absolutely will not support health care reform if it contains the Senate language. That would be too many defectors, since health care reform cannot pass the House a second time if Pelosi loses three or more votes. 

Fox News' Jim Angle contributed to this report.