LANSING, Mich. (AP) — A group that supports lifting restrictions on embryonic stem cell research in Michigan has filed paperwork with the state that could lead to a ballot proposal for its effort.

The drive to allow more embryonic stem cell research could target the November 2008 ballot. But supporters said Thursday the effort is exploratory at this point and more work needs to be done before they would decide to proceed.

"We're strictly exploring the possibility right now," said Dave Waymire, a Lansing-based spokesman for the group. "There are a lot of things that still would have to be done."

Chief among the tasks would be fundraising for a potentially costly campaign and the collection of thousands of signatures of Michigan voters. It would take 380,126 signatures to get an issue on the ballot to change the state constitution or 304,101 signatures to put a legislative proposal before state lawmakers.

The campaign would be opposed by the Michigan Catholic Conference and other groups that oppose lifting restrictions on embryonic research.

Those groups would rather focus on adult stem cell research to avoid what it considers moral complications of embryonic research because it involves the destruction of embryos.

"Human life is not a commodity that can be created and killed in an effort to generate profits and patents," Michigan Catholic Conference President and CEO Sister Monica Kostielney said in a statement.

Supporters of adult stem cell research say it has substantial promise to help cure diseases and chronic ailments. The Catholic Conference this month started an informational campaign related to the topic.

But embryonic stem cell research supporters say their methods hold greater potential to address illnesses including Parkinson's, spinal cord injuries and juvenile diabetes.

State law does not permit Michigan researchers to get embryos left over from fertility treatments in the state. State scientists can use embryonic stem cell lines from California, Illinois or other states with less restrictive laws, but those lines sometimes are patented by other researchers.

State Rep. Andy Meisner, a Democrat from Ferndale, said Thursday he still is hopeful his legislation that would lift research restrictions could pass the Legislature. But if it doesn't, he said, groups that support the research may look at alternatives such as the ballot proposal.

"There is a growing statewide coalition of patients and advocacy groups who feel passionately about the need for this change in Michigan law," Meisner said.