Battling over birth control

>>> now to a new front in the battle over abortion. this week voters in mississippi will decide whether to back an amendment to the state constitution defining life as beginning at the moment of conception. there are some consequences of that bill that have a lot of women concerned. we get our report from nbc's thanh truong.

>> reporter: to supporters of mississippi 's initiative 26, life begins at fertilization.

>> this is an opportunity to define what a person is.

>> reporter: the anti-abortion measure is known as the person hood amendment. it seeks to change the state's definition of a person to include, quote, every human being from the moment of fertilization, cloning or equivalent thereof.

>> please go to the polls, bring justice to the unborn, and stop the innocence from being killed.

>> reporter: while supporters say the amendment would not ban contraceptives, it would prohibit post conception methods like the morning after pill and intrauterine devices. and in rape or incest --

>> an innocent baby conceived through rape or incest from being executed for the crime.

>> reporter: opponents say all of this goes too far, that women have the right to choose.

>> i don't like the state being able to tell me, you know, you have to do it now or you have less options to plan your family.

>> it gives politicians the right to reach in and interfere with the most intimate and difficult personal decisions that a woman and a family has to make. it is wrong.

>> reporter: opponents argue the language is too broad, and could be applied to such matters as the destruction of embryos created by in vitro fertilization, possibly making it illegal. person hood usa, the organization behind the movement, twice tried to get similar amendments passed in colorado. next year it is targeting florida, indiana, ohio and oregon. its goal to repeal roe v. wade , the u.s. supreme court decision that legalized abortion.

>> if it makes its way up to the supreme court , and they rule that person hood is constitutional, then that does open up a window to overturn roe v. wade .

>> reporter: on tuesday in mississippi , one of the most private decisions will be the focus of a public referendum. thanh truong, nbc news.