Gay rights campaigners are advising Conservative MP Peter Bone not to marry another man after he branded same-sex marriage "completely nuts".
The Wellingborough MP was speaking about government plans to legislate for same-sex marriage.
Bone, a Christian, asked fellow Tory MP and a church commissioner in parliament Tony Baldry on what representations the church will be making in the consultation.
"Would it not be very simple just to write back and say 'Marriage is between a man and a woman so this is completely nuts'?" asked Bone.
"Our strong advice to opponents of same-sex marriage is not to get married to someone of the same sex," Andrew Wasley, media manager for gay rights charity Stonewall, told International Business Times UK.
"There is this erroneous concern that two same-sex people getting married is going to undermine marriage for everyone else, which is simply nonsense.
"A lot of the people who say that gay marriage will undermine straight marriage said much the same thing about civil partnerships and that has proved to be utterly incorrect."
Wasley added: "We make it very clear that we do not want to force any religion to conduct same-sex marriage ceremonies. We believe very deeply in religious freedom."
Critics are taking issue with Bone's reference to the idea of same-sex marriage as "completely nuts".
Some took to Twitter to condem Bone.
"How are MPs still able to get away with flippant ignorant homophobic comments?" asked Mel Sanson.
"Shame on Peter Bone MP denouncing gay marriage. Gay people represent a large proportion of the electorate and deserve equal rights," Angela Lester wrote.
The Home Office, which is conducting the consultation, affirmed its commitment to same-sex marriage.
"If a couple love each other and want to commit to a life together, this government believes they should have the option of a civil marriage irrespective of their sexual orientation," a spokeswoman said.