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A bill that would ban sex-selective abortions failed to muster enough support to pass the House Thursday following a contentious debate.

The final vote was 246-168. Though a majority voted in favor of the bill, this particular proposal required a two-thirds majority to pass -- supporters of the bill fell 30 votes short.

The proposal would have made it a federal crime to carry out an abortion based on the gender of the fetus. The measure takes aim at the aborting of female fetuses, a practice more common to countries such India and China, where there is a strong preference for sons, but which is also thought to take place in the U.S.

The White House and Democratic lawmakers opposed the bill out of concern that it could end up subjecting doctors to strict punishment, suggesting the law would be difficult to follow.

"The administration opposes gender discrimination in all forms, but the end result of this legislation would be to subject doctors to criminal prosecution if they fail to determine the motivations behind a very personal and private decision," White House Press Secretary Jay Carney said Thursday.

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    But GOP lawmakers pointed to the opposition as further proof of the administration's abortion advocacy.

    "It is inconceivable to me how our Nobel Prize-winning president can refuse to protect little girls from the violence of sex-selection abortion," Rep. Chris Smith, R-N.J., said Thursday.

    Bill sponsor Rep. Trent Franks, R-Ariz., said "there has never been a more pro-abortion president in the White House ... I'm astonished the leader of the free world would fail to protect the unborn from being aborted on the basis of sex."

    The mainly Republican supporters of the bill characterized the vote as a sex-discrimination issue at a time when Democrats are accusing Republicans of waging a war on women. A day before the vote, Planned Parenthood also launched an ad against GOP presidential candidate Mitt Romney accusing him of planning to "deny women the right to make their own medical decisions."

    The legislation would have made it a federal offense, subject to up to five years in prison, to perform, solicit funds to perform or coerce a woman into a sex-selection abortion. Bringing a woman into the country to obtain such an abortion would also be punishable by up to five years in prison.

    Franks and others say there is evidence of sex-selection abortions in the United States among certain ethnic groups from countries where there is a traditional preference for sons. The bill notes that countries such as India and China, where the practice has contributed to lopsided boy-girl ratios, have enacted bans on the practice.

    But the Guttmacher Institute, an organization that favors abortion rights, said evidence of sex selection in the United States is limited and inconclusive. It said that while there is census data showing some evidence of son preference among Chinese-, Indian- and Korean-American families when older children are daughters, the overall U.S. sex ratio at birth in 2005 was 105 boys to 100 girls, "squarely within biologically normal parameters."

    Marcia Greenberger, co-president of the National Women's Law Center, said the bill fosters discrimination by "subjecting women from certain racial and ethnic backgrounds to additional scrutiny about their decision to terminate a pregnancy."

    The Associated Press contributed to this report.