* Legal challenges seen if measure passes
* Similar efforts coming in other states in 2012
By Colleen Jenkins
Nov 5 (Reuters) - Mississippi on Tuesday could be the first U.S. state to define a fertilized egg as a person, a controversial concept aimed at outlawing abortion, some types of birth control and infertility methods that result in the loss of embryos.
The so-called personhood amendment to the state constitution represents a twist in strategy for anti-abortion rights efforts, which have notched great success across the country this year with dozens of new legal restrictions.
Proponents of the Mississippi ballot initiative said a win on Tuesday would bolster similar efforts geared for the 2012 elections in states including Florida, Ohio and Colorado. They said it would help their ultimate goal of overturning Roe v. Wade, the 1973 U.S. Supreme Court decision making abortion legal.
"Mississippi is one step in a lengthy process," said Jennifer Mason, spokeswoman for the Colorado-based Personhood USA organization. "We're looking at a coordinated effort from many states in order to see real change in the United States."
Critics of the Mississippi measure say defining a person as "every human being from the moment of fertilization, cloning or the functional equivalent thereof" amounts to an extreme government intrusion that could effectively criminalize routine medical care and endanger women's lives.
Opponents, including the state's medical and nurses associations, have stepped up their criticism in recent weeks, leading to dueling news conferences and fact sheets presenting each side's version of the likely effects of the action.
All agree the proposed amendment would ban abortion without exceptions for rape or incest victims and also outlaw some forms of hormonal contraceptives, though there is dispute over which ones.
Advocates say the initiative would not bar in-vitro fertilization but would prevent unused embryos from being destroyed. They argue critics have resorted to "scare tactics" in claiming doctors would be kept from performing life-saving treatments for women with medically complex pregnancies.
"It's not really scare tactics. We're really scared," said Dr. Randall Hines, an infertility specialist in the Jackson, Mississippi, area. "This amendment represents the greatest moment of government interference in the delivery of health care that we've ever seen."
PAST 'PERSONHOOD' VOTES FAILED
The two previous attempts to get voters to declare a fertilized egg a legal person were in Colorado in 2008 and 2010, and both efforts failed to pass by wide margins.
But the political climate has been friendly toward tightening abortion laws this year. Eighty-four new restrictions became law, the most ever in such a short stretch, said Elizabeth Nash, public policy associate at the Guttmacher Institute, which studies reproductive health issues.
In Mississippi, a conservative and religious state with a single abortion clinic, backers of the personhood amendment collected more than 100,000 signatures from registered voters to get the initiative on the ballot.
The Republican and Democratic gubernatorial candidates each have pledged support for the amendment.
The initiative will probably pass but likely not withstand the anticipated legal challenges, said Marty Wiseman, director of the John C. Stennis Institute of Government at Mississippi State University.
"Mississippi can't negate Roe v. Wade, which this would do," he told Reuters. But "who knows the twists and turns it is going to take before it is shot down by the Supreme Court."
Though many faith leaders favor the amendment, the solidly anti-abortion rights Catholic Diocese of Jackson and other religious leaders have spoken out against it as an ill-advised approach that will either get struck down by federal courts or lead to a judicial reaffirmation of abortion rights.
"The unintended effect would very likely jeopardize current protections in state law and cause a loss of momentum in the ultimate goal of establishing full legal protection of the unborn from the moment of conception," the diocese said in a statement.
Dr. Freda Bush, a Jackson obstetrician gynecologist who has been a vocal proponent of the ballot initiative, said she hoped voters recognized that the measure would not disrupt the sound practice of medicine but instead would re-establish "a culture of life" in Mississippi.
"If we're going to value life and protect life after it's born, why not start at the beginning?" she said. (Editing by Greg McCune and Jackie Frank)
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