One of the Legislature's most vocal opponents of same-sex marriage says homosexuality is a choice and form of sexual addiction.

"It's an unhealthy, sexual addiction," state Rep. Glenn Gruenhagen said Wednesday.

The Glencoe Republican said he has a friend who ran a sexual addiction clinic. "He helped many homosexuals and other people come out of the lifestyle."

Gruenhagen made the statements after advocates unveiled their proposal to legalize same-sex marriage, which would make Minnesota among nearly a dozen states that allow gays and lesbians to wed.

"When we talk about gay marriage, we are not talking about an immutable characteristic, like the color of your skin." Gruenhagen said. Referencing a decade- old genome study, he added: "There is no gay gene. The concept that there is a gay gene is an unscientific lie."

The scientific and medical community have debated the nature of homosexuality for years. Most of the leading medical and scientific experts say that homosexuality is not a choice, but a mix of biological and environmental factors.

In Gruenhagen's home county of McLeod, 65 percent of voters supported a proposed Constitutional amendment to define marriage as a union between one man and one woman.