CHEYENNE - Gay marriage opponents told a Senate committee Friday they feared what could happen to the institution of marriage if a bill that would give Wyoming the authority to void other states' gay marriages doesn't pass.

Massachusetts is the only state that currently grants marriage licenses to same-sex couples; others permit civil unions, but the proposed law only pertains to gay marriages.

Wyoming already has a law in place that mandates marriages conducted in the state must be between a man and woman.

"The bill simply says we would not have to honor same-sex marriages in Wyoming that were authorized in some other state," the bill's sponsor, Sen. Gerald E. Geis, R-Worland, said.

Thea Adamo of Wheatland said the bill was necessary because "activist forces are at work in our nation and here in this room that would warp and destroy the institution of marriage."

"How would Wyoming deal with the added cases involving child custody, adoption, insurance - both private and business - medical and educational costs that will undoubtedly impact our state?" Adamo said.

Jason Marsden, the partner of former Casper mayor and current city councilman Guy Padgett III, said he's not an activist, and that he wasn't trying to get Wyoming to legalize gay marriages. However, he said he used to live in Massachusetts and that he and Padgett might return there one day.

"Were we to do so, we would probably avail ourselves of our rights as Massachusetts citizens to be married," Marsden said. "We would hate to not be able to come back to Wyoming in order to protect our form of relationship, which, I assure you, is something that we take very seriously."

The same-sex marriage bill is Senate File 13.