MADISON, Wis. -- There's an effort to overturn the embryonic stem cell patents held by the Wisconsin Alumni Research Foundation.

A consumer watchdog group is challenging three stem cell patents held by the Wisconsin Alumni Research Foundation, which is the University of Wisconsin-Madison's patenting and licensing arm.

The California group is asking the U.S. Patent and Trademark Office to reconsider whether the patents are justified.

Two patents cover the methods to derive and grow stem cells. The third patent involves a method to grow stem cells without animal products.

The group claims WARF is collecting money it doesn't deserve and that the patents slow the progress of stem cell research.

"I think it's really born in the fact that they'd like to use the patents to build their program for free. We're certainly willing to work with them to find an equitable solution, somewhere between collaboration and a license I'm sure there's a solution, and we continue to talk with them about that," said Elizabeth Doyle, director of Business Development for the Wisconsin Alumni Research Foundation.

The patents have been granted to more than 300 academic researchers for free, and 12 commercial entities.