(Updates throughout)

By Maggie Fox, Health and Science Editor

WASHINGTON, Jan 23 (Reuters) - The U.S. Food and Drug Administration has cleared the way for the first trial to see if human embryonic stem cells can treat people safely, a company involved in the controversial research on Friday.

Geron Corp (GERN.O: Quote, Profile, Research), a California biotechnology company, said it plans a clinical trial to try to use the stem cells to regrow nerve tissue in patients with crushed, but not severed, spinal cords.

The issue of human embryonic stem cell research has been a political touchstone, with anti-abortion forces backed by former president George W. Bush arguing the technique involves the destruction of human embryos. Advocates say it could transform medicine.

"For us, it marks the dawn of a new era in medical therapeutics. This approach is one that reaches beyond pills and scalpels to achieve a new level of healing," Geron Chief Executive Dr. Thomas Okarma said in a telephone briefing.

Shares of Geron rose more than 53 percent to $8 in mid-morning trading on Nasdaq after touching $8.38.

Geron will recruit eight to 10 recently injured patients and inject them with small numbers of human embryonic stem cells manipulated to become the oligodendrocyte cells that insulate nerves, and that produce compounds to stimulate the growth of nerve cells.

Okarma said there was no political significance to the announcement coming the same week as President Barack Obama took office. Obama has been widely expected to lift restrictions on federal funding and support of human embryonic stem cell research.