A Republican congressman in Minnesota has said that homosexuality is a choice and a form of “sexual addiction.”

Glenn Gruenhagen made the statements on Wednesday following the unveiling of a proposal to legalise same-sex marriage in the state, reports the Star Tribune.

Of homosexuality he said at a press conference: “It’s an unhealthy sexual addiction.”

“So the concept that you’re born that way and it’s an immutable characteristic is an unscientific lie, OK?” Mr Gruenhagen continued. “The human genome map has been completed. I urge you, as the news media, to give both sides a fair and open hearing on this debate.”

The congressman, who represents Glencoe, Minnesota, also spoke about gay conversion therapy, saying he had a friend who ran a clinic for sexual addiction.

“He helped many homosexuals and other people come out of the lifestyle,” claimed Mr Gruenhagen.

He added: “When we talk about gay marriage, we are not talking about an immutable characteristic, like the colour of your skin.

Last November, a referendum to cement a ban on same-sex marriage into Minnesota’s constitution was defeated.

In Mr Gruenhagen’s home county, 65% of voters supported the proposed constitutional amendment to define marriage as a union between one man and one woman.

However, several lawmakers are now seeking to legalise equal marriage in the state.