The U.S. Patent and Trademark Office announced Tuesday that it intends to review patents for embryonic stem-cell research held by the Wisconsin Alumni Research Foundation.

These patents cover work done by University of Wisconsin researcher James Thomson, the first to isolate and grow human embryonic stem cells.

The decision to re-examine the patents came after the Foundation for Taxpayer and Consumer Rights and the Public Patent Foundation alleged they were not valid.

The patents give WARF rights to five embryonic stem-cell lines grown and held at the UW-affiliated WiCell Research Institute and the methods used to culture them. The California-based FTCR and the Public Patent Foundation, based in New York, charge that the patents should never have been issued.

The groups assert that although Thompson was the first to culture human embryonic stem cells, his techniques were not innovative enough to warrant a patent.

John Simpson, the stem-cell project director for FTCR, said another researcher would have ultimately developed Thompson's methods.

"The key elements of discovery here were done 15 years before by people that never sought patents," Simpson said.

Another claim made against the patents is that the USPTO is giving WARF too much power in the area of nation-wide stem-cell research, thereby discouraging U.S. researchers and even sending some projects overseas.

"[Patents] are being used in a harmful way at the moment that is impeding research across the United States," said Dan Ravicher, executive director of the Public Patent Foundation.

Scientists who request stem-cell lines from the research foundation must receive licenses before their work can go ahead. Companies can be charged up to $400,000 and WARF claims royalties on products produced using the patents.

However, more than 300 academic research groups have received free licenses and cells from WARF. Hoping to use the patents to benefit the state, Gov. Jim Doyle said last week that universities in Wisconsin and companies that fund nonprofit organizations will have their licensing fees waived.

WARF attributes the challenge from the two groups to political and financial incentives. California is making efforts to become a leading force in stem-cell research with a $3 billion grant program.

"The patent office grants over 90 percent of the requests for reexamination, so this decision does not come as a surprise," said Beth Donley, executive director of WiCell Research Institute and special counsel to WARF in an Associated Press article. "WARF believes the … patents are valid."

The review process allows WARF to make an opening statement about the claims made against the patent, which can then be rebutted by FTCR and Public Patent. An initial decision is likely to take a few months, but appeals may not be finished for several years.

–The Associated Press contributed to this article.