For the second time in two years, the House voted Wednesday to pass legislation that would ban almost all abortions 20 weeks or more after fertilization. The bill, called the Pain-Capable Unborn Child Protection Act, claims that “an unborn child is capable of experiencing pain at least by 20 weeks after fertilization,” though medical evidence does not support this.

Of course, the bill is not really about scientific findings of any sort. It is simply another attempt by conservative Republicans to undercut women’s constitutionally protected reproductive rights. A 20-week abortion ban would be a restriction before fetal viability that violates the Supreme Court’s ruling in Roe v. Wade.

The House passed a 20-week ban in 2013, but the Senate never voted on it. House Republicans had planned to vote on a 20-week ban again this January, but that was stalled when some Republican members objected to the bill’s language prohibiting rape victims from getting an abortion unless they had reported their rape to the police.

The measure gained momentum after The New England Journal of Medicine published a study indicating that a tiny number of babies born at 22 weeks can survive if given intensive medical treatment. Representative Diane Black of Tennessee, one of the bill’s sponsors, released a statement last Friday saying, “Science tells us that, after 20 weeks, babies can feel pain and are increasingly able to live outside the womb.”