By Matthew Davis
BBC News, St Louis, Missouri
The politics of stem cell research are as complex as the science itself
A cluster of banners opposing stem cell research sit beneath a picture of the Pope inside the rectory of St Pius V Catholic church, in the city of St Louis.
It is a striking symbol of a bitter and emotional debate - a cocktail of science, religion and party politics - that is overshadowing the mid-term elections here in Missouri.
When voters in this part of Middle America go to the polls to elect their representatives, they will also be asked to decide on "Amendment Two" - changing the state constitution to permit federally-approved research on human embryos.
The politics of this topic are almost as complicated as the science itself.
In July, President George W Bush vetoed a bill that would have expanded federal funding for new embryonic stem cell research.
But the president appears to be out of step with most Americans, 56% of whom are for the research and 32% against, according to a poll conducted by the Pew Research Center in August 2006.
In the words of the Catholic Church here, it is "a most disturbing advance of the culture of death, with dire implications for our whole nation".
Yet for advocates, the prospects of new medical cures outweigh the destruction of the potential life of human embryos involved in the research.
If Amendment Two passes it will mean Missouri joining California as the only states to make research a constitutional right.
Mr Bush appears to be out of step with most Americans on the issue
Across Missouri, more than $28m (£15m) has been spent by backers of the "yes" campaign, the vast majority of this from Jim and Virginia Stowers, founders of the Stowers Institute for medical research in Kansas City.
However, a less well-funded but vigorous "no" campaign by groups like Missourians Against Human Cloning has put the outcome of the referendum in some doubt.
Irvin Harrell is political editor of the St Louis Post-Dispatch newspaper.
"A lot of people here are pro stem cell, the majority is pro, but there are grassroots groups that are starting to build momentum.
"It makes you wonder; the 'yes' guys are spending $28m, the other side just two or three million, but when you look around the streets you see a helluva lot more signs against the amendment.
"They are taking a cue from the Sunday services. The churches are preaching this every Sunday - they are drilling people out to vote 'no' at the polls, with the message that this is God's will."
Tony Huenneke, spokesman for the Catholic Church in eastern Missouri - has no qualms.
"Sure the bishops have taken a position against it," he says. "We are urging people to vote 'no', rather we are educating people to vote 'no'."
Plea for calm
On a chilly Thursday night another form of education is taking place at the St Louis Science Center.
Both sides are "educating" supporters on the issues
A few dozen Missourians have come to hear two experts discuss the science and ethics of stem cell research.
Professor Gerard Magill, a Scot who teaches at the Center for Health Care Ethics at St Louis University, is troubled by the belligerent nature of the debate.
"This is not religion versus science," he urges. "There are people of faith and people of goodwill on both sides of the argument.
"This is an important subject to us all, but one worthy of calm deliberation, respect and restraint, and of civil discourse."
Certainly there are some religious groups backing both campaigns. But some in his audience aren't convinced a respectful dialogue is always possible.
"I can't even talk about this to my friends," says one woman, who does not want to give her name.
"They are all church-goers and they tell me, 'Why would you even want to talk about it? It is a no vote, that's it'."
According to a new report from the Pew Research Center, Americans "cannot be easily characterised as conservative or liberal on today's most pressing social questions".
Jim Talent and Claire McCaskill are fighting over a senate seat
"Despite talk of 'culture wars' and the high visibility of activist groups on both sides of the cultural divide, there has been no polarization of the public into liberal and conservative camps," the organisation says.
When it comes to party politics, this is an issue that cuts across the lines of Republicans and Democrats.
Perhaps this is why in increasingly bitter battle being fought over who will be Missouri's next US senator, the protagonists are stepping gingerly around the subject of stem cells.
Polls show Democrat Claire McCaskill - in the 'yes' camp - and incumbent Republican Jim Talent - in the 'no' camp - locked in a dead heat
in a seat seen as crucial for Democratic hopes of retaking the Senate.
Irvin Harrell says: "It took a while before the candidates took any sort of stance on the issue.
"Now, the bottom line is that it is such a controversial issue that it is tough to align yourself for or against it if you want to get anything from the middle ground."
Ironically, despite the sound and fury over stem cells, it may be other issues that fire voters to the polls - and have a bearing on the election.
Missouri is also considering ballot initiatives on raising the minimum wage to $6.50 per hour, and putting up to 60 cents on a packet of cigarettes.
Harrell says: "We have a lot of blue-collar, Democrat-leaning people in the cities here that might say 'You can mess with the origins of human life,
but don't mess with the price of my smokes'.
"If that's an issue that drags people to the polls, they'll probably tick a box for their candidate at the same time."