Health researchers need alternatives to using fetal tissue, Department of Health and Human Services leaders have said after several years of controversy and investigations into whether fetal tissue procured from aborted babies was sold illegally.

HHS Assistant Secretary of Health Brett Giroir sent a letter to U.S. Rep. Mark Meadows (R-N.C.), chair of the Freedom Caucus, saying HHS did too little to find alternatives under previous administrations and there need to be "adequate alternatives" to scientific research involving human fetal tissue.

The letter, which a source shared with the news site Politico, said HHS is "fully committed to prioritizing, expanding, and accelerating efforts to develop and implement the use of these alternatives." He described HHS as "pro-life and pro-science" under President Donald Trump.

The letter appears to back "scientifically validated and reproducible" models as among possible alternatives.

Scientists who back fetal tissue research say there are few alternatives. They argue the tissue would otherwise be discarded, and there are already ethical safeguards in place. They say fetal tissue research has been instrumental in developing vaccines and understanding phenomena like how the Zika virus affects the brains of unborn children. They say fetal tissue aids Alzheimer's disease and Parkinson's disease research, as well as research in childhood developmental disorders.

A 1993 federal law allows the use of fetal tissue from elective abortions that would otherwise be discarded. However, the sale of such tissue is also barred by law.

Mallory Quigley of the Susan B. Anthony List told Politico her group would continue to advocate defunding fetal tissue research "as soon as possible." She said her group is hopeful "that HHS will reach a new policy consensus that better reflects the administration's pro-life position."

Caitlin Oakley, an HHS spokesperson, said the agency has not made an official decision on whether to fund more fetal tissue research.

"We continue to go through a thoughtful, deliberative process given the scientific ethical and moral considerations involved," she told Politico. "When we receive inquiries from members of Congress, we respond."

A series of undercover investigations from journalists with the Center for Medical Progress, first released in 2015, appear to show several leaders in the abortion industry involved in the illegal sale of fetal tissue from aborted babies.

The investigation has had legal consequences for some procurers of fetal tissue.

DV Biologics and DaVinci Biosciences, two bioscience companies, admitted fault, ceased California operations and agreed to meet the terms of a legal settlement close to $7.8 million in value for violating state and federal laws against the purchase or sale of fetal tissue.

Following two investigations, Congressional committees have made criminal referrals for both Planned Parenthood and Advanced Bioscience Resources, a non-profit company, for alleged involvement in illegal fetal tissue sales. There is an active Department of Justice investigation based on the criminal referrals.

There are also criminal charges against the Center for Medical Progress investigators, as well as civil lawsuits. These allegations include claims that the videos were filmed illegally in violation of privacy laws.

Federal funding for fetal tissue is now under review. As part of the review process, senior officials at HHS held an off-the record, invitation-only listening session on Nov. 16 with leaders in medical research fields.

Participants included leaders with the American Society for Cell Biology, the Federation of American Societies for Experimental Biology, the Society for Neuroscience and the International Society for Stem Cell Research.

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The inquiry has prompted opposition from pro-abortion rights groups.

Mary Alice Carter, director of Equity Forward, which backs fetal tissue research and monitors pro-life groups, charged that HHS secretary Alex Azar "continually kowtows to anti-abortion groups while ignoring the scientific and medical communities," Science magazine reports.

The National Institutes of Health gave out about $103 million in 2018 for research involving fetal tissue.

In July 2018 the Food and Drug Administration gave a $15,900 contract to Advanced Bioscience Resources for "fresh human fetal tissue," which would be transplanted into mice in order to create human-like immune systems for research purposes. It is the eighth contract between the FDA and the company since 2012, and seven of the contracts appear to relate to the same or similar programs.

HHS cancelled the contract after receiving protests and criticism from several Members of Congress, who said they were alarmed that the tissue procurement contracts continued despite the "serious unresolved questions" uncovered by House and Senate investigations.

In 2010 a federal judge ruled that federally funded human embryonic stem cell research was against the law. That ruling resulted in a 19-day halt on related in-house National Institutes of Health projects, but NIH funds that had already been given to external researchers were not affected, the magazine Science reports.