After a long Wednesday considering airport security screenings and fireworks regulations, the House State Affairs Committee tried its hand at medical science, with Rep. Jodie Laubenberg’s proposal to ban abortions after 20 weeks.

Back in January, Gov. Rick Perry said a “fetal pain” bill like House Bill 2364 was one of his priorities for the session. The measure is based on the pseudoscientific argument that fetuses can feel pain 20 weeks after conception, a hot sub-debate within the fight over abortion access.

State Affairs, which also heard last session’s pre-abortion sonogram bill, is at the center of the women’s health debate again this session. Having already debated Wednesday whether abortion raises a woman’s risk of breast cancer (it doesn’t), the committee grappled with even deeper scientific questions with Laubenberg’s bill.

Laubenberg and Rep. Jessica Farrar (D-Houston) argued right off the bat about how to determine the age of the fetus. Laubenberg said that determining the age by the last menstrual period was more medically subjective that pinpointing the exact moment of sperm-hits-egg conception. Farrar disagreed. “This is quite the opposite,” she said.

Laubenberg told lawmakers she had a slew of peer-reviewed studies supporting “fetal pain” science. The pro-life group Texas Right to Life also circulated a video Wednesday featuring freshman Rep. Greg Bonnen (R-Friendswood), a neurosurgeon, to explain the “science” behind the 20-week theory.

As Rep. Farrar pointed out numerous times throughout the hearing, a 2005 study from the Journal of the American Medical Association discredits the theory. According to JAMA, “Pain perception requires conscious recognition or awareness of a noxious stimulus,” and the capacity for a fetus’s perception of pain probably doesn’t exist before 29 or 30 weeks. Another study by University College London determined fetuses do respond to painful stimuli, but not until 35 to 37 weeks, which would be close to birth.

“I will very gladly place my studies against your studies,” Laubenberg told Farrar.

Some doctors from Texas and out-of-state backed Laubenberg. “I have the deep impression that these babies … have a nervous system developed enough to responds to pain,” Galveston doctor Patrick Nunnelly said.

Laubenberg’s bill would ensure that a doctor who induces, or attempts to induce, an abortion in violation of the 20-week rule can’t to renew their medical license. The bill would prohibit releasing the identity of a woman whose abortion had come after 20 weeks without her permission—or a judge’s ruling.

The bill also mandates that a woman seeking an abortion must have the physician determine the post-fertilization age of the fetus, must get a second opinion on the age of the fetus from another physician and the physician performing the abortion should provide “the best opportunity for the unborn child to survive.”

The legislation provides an exception to this 20-week rule only if the woman is in danger of death or physical impairment if she does not get the abortion. Psychological harm to the woman is not taken into account. There is no exception if the woman is healthy except for risks if she takes the pregnancy to term, or if a medical diagnosis states that there is only a potential for the woman’s death or physical harm. There’s no exception based on the health of the fetus.

Critics of the bill testified that it’s irresponsible to ignore special cases like those, since abortions after 20 weeks often involve rare circumstances.

Whether the science behind the bill is faulty or not, ACLU Legal and Policy Director Rebecca Robertson said the bill’s provisions are unconstitutional. A report released earlier this month from the Guttmacher Institute noted that since Roe v. Wade, the U.S. Supreme Court has ruled that states may only restrict or ban abortions after proving the fetus could survive after birth, but that “even after fetal viability, states may not prohibit abortions ‘necessary to preserve the life or health’ of the woman.”

Laubenberg, Texas’ state chair for the American Legislative Exchange Council, noted how popular these 20-week abortion bans have been across the country lately. Ten states—Alabama, Arkansas, Arizona, Georgia, Idaho, Indiana, Kansas, Louisiana, Nebraska and Oklahoma—have already enacted 20-week abortion bans. Though Idaho’s was recently rejected by a federal judge, similar bills are working their way through other state legislatures.

The committee left the bill pending.