The U.S. Patent and Trademark Office has issued a preliminary rejection of three stem cell patents held by the University of Wisconsin-Madison.
The patents were rejected because the discoveries by researcher James Thomson were "obvious to one of ordinary skill," the patent office said.
The Wisconsin State Journal says the non-profit Wisconsin Alumni Research Foundation will appeal the rejection.
The patents, which cover virtually all stem cell research in the country, have brought in at least $3.2 million and "could net much more money before they expire in 2015," the newspaper said.
Companies wanting to study the cells must buy licenses costing $75,000 to $400,000. The newspaper said WARF recently started waiving the fees if the research is conducted at universities or by non-profit groups.
Critics of the patents say the fees have driven some stem cell research overseas.
Copyright 2007 by United Press International
Explore further: Bribery 'hits 1.6 billion people a year'