This November, Mississippi will serve as a test case on a life-at-fertilization initiative that its backers are hoping will launch the next wave of court challenges to Roe v. Wade.

A national effort to put abortion bans into state constitutions is looking for its first victory next month in Mississippi, where voters are being asked to approve an amendment declaring that life begins when a human egg is fertilized.

Supporters hope the so-called personhood initiative will succeed in a Bible Belt state that already has some of the nation’s toughest abortion regulations and only a single clinic where the procedures are performed.

The initiative is endorsed by both candidates in a governor’s race that’s being decided the same day. While Mississippi is the only state with such an amendment on the ballot this fall, efforts are under way to put the question to voters in at least four other states in 2012.