Sensible Sentencing Trust spokesman Garth McVicar is standing by his claim that legalising gay marriage could increase crime, despite a backlash on social media.
Since Mr McVicar's submission to Louise Wall's Marriage (Definition of Marriage) Amendment Bill was made public yesterday, a wave of protest tweets were posted on Twitter, many using the hashtag #gaycrimewave.
Broadcaster Alison Mau, who is engaged to her female partner, wrote: "I'm oddly grateful for his help in getting the bill passed."
Gay Labour MP Grant Robertson posted: "welcome, all crimes, grammatical or otherwise, are a result of my deviance."
Yesterday, Mr McVicar said his submission was personal and not on behalf of the trust and he stood by his claims.
"If you look at the court stats, most of the crime that has been committed has been committed by fatherless kids."
He said if the bill were passed, same-sex couples might be able to adopt children.
"That's where it's heading - this is just another step in that politically correct journey that we've been on as a country."
It wouldn't matter that some children, if adopted by a gay couple, had two fathers, because they would still need a mother, he said.
Green Party MP Kevin Hague, who sits on the select committee considering the bill, said that of the 20,000 submissions on the proposals, Mr McVicar's was the only one to link gay marriage with crime.
He said it mirrored a number of other submissions connecting gay rights with an erosion of traditional values, which was associated "in a vague way to various ills in society".
"They are statements of probably genuinely held belief, but entirely absent of actual argument or evidence."
Campaign for Marriage Equality chairman Rawa Karetai said Mr McVicar's submission was far-fetched and he would be interested to see some peer-reviewed studies on the subject.
Mr McVicar made the submission last month.
It said: "I see the marriage amendment bill as being a further erosion of what I consider to be esential [sic] basic values and morals that have stood the test of time for centuries."