Health and Human Services Secretary Alex Azar meets with staff members of the Centers for Disease Control and Prevention in March. (Melina Mara/The Washington Post)

The Trump administration has launched a review of all federally funded research that uses fetal tissue and has canceled one contract for such material, stepping into a decades-old controversy that has been a sidelight to the ideological war over abortion.

Federal health officials dispatched a letter Monday ending a contract with a California-based nonprofit group targeted by social conservatives in Congress and a coalition of antiabortion and faith-based groups. In July, the Food and Drug Administration had agreed to pay the organization, Advanced Bioscience Resources, nearly $16,000 for fetal tissue that was to be implanted into mice for research into immune responses to drugs.

The cancellation of the relatively small contract was followed hours later by an announcement from the Department of Health and Human Services with far broader implications. The department said it has begun auditing “all acquisitions involving human fetal tissue” to make sure they comply with laws and regulations. The Monday night statement also said HHS has begun “a comprehensive review” of all fetal tissue research “in light of the serious regulatory, moral, and ethical considerations involved.”

The prospect that the administration could restrict — or eliminate — government support for fetal tissue research immediately alarmed biomedical scientists, who say that such tissue has been vital in testing new vaccines, exploring Parkinson’s disease treatments and understanding the transmission of HIV.

Both supporters of such research and its opponents said they were uncertain whether HHS’s unprecedented review was intended largely as a bold symbolic step to appease the administration’s conservative allies or is a precursor to abolishing federal funding of fetal tissue, which has been employed in studies since the 1930s.

An HHS spokeswoman on Tuesday declined to say how many government contracts or research projects the department plans to review, how long the inquiry is expected to take or whether the canceled contract’s perceived defect, which was not identified, is commonplace. A National Institutes of Health listing of funding shows that, last year, $98 million was devoted to fetal tissue research, mainly in grants to scores of academic researchers.

Asked whether those grants are part of the review, the spokeswoman, Caitlin Oakley, said, “We do not comment on ongoing reviews and audits.”

HHS is taking the steps in coordination with House Republicans, the most recent in a series of moves by the department since President Trump took office that align with the longtime agenda of social conservatives.

House Speaker Paul D. Ryan (R-Wis.) “worked with [HHS Secretary Alex] Azar” to address the immediate problem” involving the ABR contract, according to a Ryan spokeswoman, AshLee Strong, who said that he “will continue to work with HHS to make sure this problem is resolved in the future.”

House Republicans had attempted, for the second consecutive year, to include a ban on fetal tissue research in legislation funding HHS for the coming year, but it is not in the final version that the Senate has passed and the House plans to vote on Wednesday.

Last week, 85 House Republicans signed a letter to FDA Commissioner Scott Gottlieb, saying they were “deeply concerned” about the ABR contract. The letter said that the nonprofit group had been part of a pair of congressional inquiries in the past two years into fetal tissue procurement and that House investigators had “uncovered evidence that ABR may have violated” longtime federal and state laws that forbid the buying and selling of human fetal tissue.

The nonprofit group did not reply to requests for comment.

The decision to review fetal tissue contracts and research comes several months after HHS, in another move that sided with social conservatives, created an office, the Conscience and Religious Freedom Division, intended to handle complaints from health-care workers reluctant to take part in an abortion, assisted death or any other medical procedure they said violates their religious or moral beliefs.

Last year, the department rewrote rules under the Affordable Care Act to allow employers or insurers to invoke religious or moral beliefs to avoid the law’s requirement that birth control pills and other contraceptives be covered as part of free preventive care. And in May, the administration proposed to prevent clinics from receiving federal family-planning funds if they perform abortions or refer patients to facilities that do.

Two weeks ago, leaders of nearly four dozen antiabortion and faith-based groups, including the Susan B. Anthony List and the Family Research Council, sent a letter to Azar complaining about the ABR contract, contending that “fetal organ procurement is highly unethical and potentially illegal” and calling on the government to “find ethical alternatives as soon as possible.”

HHS said in its announcement that it “will ensure that efforts to develop such alternatives” to use of fetal tissue for research “are funded and accelerated.”

Debate surrounding the ethics of using fetal tissue in research grew more heated after the Supreme Court legalized abortion in 1973, and abortion opponents have long urged the government to ban such research. In the late 1980s, after a federal advisory panel examined the question of transplant research involving fetal tissue and concluded that it was acceptable, but a moratorium was placed on such studies until it was lifted in 1993 by President Bill Clinton. The issue has waxed and waned in prominence ever since.

Critics of fetal tissue research have argued that more modern alternatives — such as using adult cell lines, “organoids” grown in a lab, or computer models — can be used, instead. But many scientists say that this isn’t true of all branches of research and that it is difficult to duplicate the flexibility and adaptability of fetal tissue.

When the House was considering a ban on such research, more than five dozen medical and research organizations protested. The groups, which included the American Pediatric Society, the International Society for Stem Cell Research and academic institutions such as Yale and New York universities, wrote to congressional leaders that such research has been important in understanding how the Zika virus affects fetal development and that clinical trials are underway using fetal tissue cells as treatments for amyotrophic lateral sclerosis and spinal cord injury.