Washington  -

Rep. Mike Castle said he may take on the issue of human cloning as he and Rep. Diana DeGette of Colorado consider their next legislative move on stem cell research.

President Barack Obama issued an executive order March 9 lifting former President George W. Bush's ban on federal funding for embryonic stem cell research, but Obama left it up to the National Institutes of Health to develop ethical guidelines.

Following a visit to NIH, Castle, a Delaware Republican, said he and DeGette, his Democratic partner on this issue, may try to codify a ban on human cloning, which some fear could be an unwelcome spin-off of embryonic stem cell research.

Their legislation may also include a provision to prevent any financial incentive for donating embryos.

"We're concerned about some of these guidelines and the ethics of all this," Castle said. "We may add some of these things into the legislation."

Castle and DeGette have long advocated research on stem cells derived from embryos that would otherwise be discarded by fertility clinics. Their pending legislation would limit research to those stem cell lines.

Embryonic stem cells, which have the potential to develop into almost any type of cell in the body, could potentially be used to treat people with cancer, Parkinson's and other diseases.