The U.S. Department of Health and Human Services said on Wednesday that it will not renew a fetal tissue research contract with the University of California, San Francisco. The contract expired on Wednesday. This decision means an end to research using tissue from aborted fetuses.

The agency also announced it would limit future research involving human fetal tissues from abortions.

“Promoting the dignity of human life from conception to natural death is one of the very top priorities of President Trump’s administration,” a statement from the Department of Health and Human Services said.

The statement also said that an audit of the program “helped inform the policy process that led to the administration’s decision to let the contract with UCSF expire.”

The Chancellor of UCSF Sam Hawgood stated that the university strongly opposes this decision.

“At UCSF, today’s action ends a 30-year partnership with the National Institutes of Health to use specifically designed models that could be developed only through the use of fetal tissue to find a cure for HIV,” Hawgood said in a statement. “We believe this decision to be politically motivated, shortsighted and not based on sound science.”

Since the 1930s, fetal tissues have been used for vaccine development. Recently, they have been of great help to advance stem cell research and the treatments of degenerative diseases such as Parkinson’s. One of the earliest advances with fetal tissue was to use fetal kidney cells to create the first polio virus vaccines, which now save an estimated 550,000 lives worldwide annually.

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The review also led to the decision to discontinue research conducted within the NIH that involves the use of human fetal tissue from elective abortions. Research projects outside of the NIH that are funded by grants from the agency will apparently not be affected during their approved project periods.

Patricia Morris, a board member of the Federation of American Societies for Experimental Biology and a professor in the reproductive health program at Rockefeller University, said that human fetal tissues derived from elective abortions are “absolutely essential” for certain biomedical research.

“There is no substitute today,” said Morris. “No reproducible, robust and clinically relevant materials are otherwise available.”