SAN FRANCISCO, Calif. -- Federal regulators said that they're preparing to toss out three key patents related to human embryonic stem cells, an action that could ease concerns over commercial control of the work.

The Wisconsin Alumni Research Foundation from the University of Wisconsin owns the patents and has 60 days to respond and seek to change the ruling by the U.S. Patent and Trademark Office, WISC-TV reported.

The ruling was made public on Monday by the Foundation for Taxpayer and Consumer Rights and the Public Patent Foundation, which challenged the validity of the patents.

UW researcher Jamie Thomson was the first to isolate human embryonic stem cells in 1997, and the university patented his discovery and has been collecting fees from researchers since.

The university said it would fight the preliminary decision by the federal regulators.