The Republican-controlled House of Delegates voted 66-32 in favor of defining the word person under state law to include unborn children “from the moment of conception until birth at every stage of biological development.”

The measure now heads to the Senate, which is evenly split between Republicans and Democrats but with Republican Lieutenant Governor Bill Bolling wielding the tie-breaking vote.

Republican Delegate Bob Marshall, an abortion opponent who introduced the legislation, said the 1973 Roe v. Wade Supreme Court decision legalizing abortion in the United States would not have been rendered if Texas state law had regarded the unborn as a person “in the full sense.”

“So this is a first step, a necessary step, but it’s not sufficient to directly challenge Roe,” Marshall said in a phone interview.

Virginia’s approach differs from failed attempts to define a fertilized egg as a legal person in Colorado in 2008 and 2010 and in Mississippi in 2011.

Virginia’s effort avoids involving a constitutional amendment like those states, instead seeking changes throughout the legal code, said Elizabeth Nash, public policy associate at the Washington-based Guttmacher Institute, which studies reproductive health issues.

But she said the intent is the same, with the measure ultimately aimed at banning abortion, contraception and infertility treatment.

“Should this bill become law, it could have a far-reaching impact on women’s access to health care,” Nash said. “No state, as yet, has adopted anything like this.”

Marshall said the measure does not have the authority to ban birth control or infertility treatment.

“Let’s just say that the imaginations of the opponents are fertile, but their arguments are sterile,” he said.

The national anti-abortion group Parenthood USA issued a statement ahead of Tuesday’s vote calling on House Republicans to strengthen the measure before considering it.

Ted Miller, a spokesman for NARAL Pro-Choice America, said state Republicans pushing the Virginia measure had hoodwinked voters after campaigning on the economy and jobs ahead of last fall’s general election, when the Republican Party gained seats in the General Assembly.

“That agenda is out of touch with the values and priorities of Virginians, as well as Americans across the country,” Miller said.