A New Zealand university professor has angered gay groups by suggesting that recipients of sperm from gay donors should be warned that the “gay gene” may be inherited.

His comments come after medics lifted the ban on gay sperm donors in reaction to protests from human rights groups.

Gay rights organisations dismissed the outburst as pathetic after Dr Frank Sin said it was “not daydreaming” to suggest that sexual orientation could be passed on to a child.

He told the Dominion Post that animal models suggested the existence of a gene that controlled sexual behaviour.

The Gay Association of Professionals spokesman Allan-John Marsh said Dr Sin’s suggestion was insulting and pathetic. He agreed that being gay was something innate, rather than a choice, but said there was no proof of a gay gene.

Mr Marsh said: “It implies that being gay is somehow inferior. It’s not a disease, not a handicap, even taking the view that you are born this way. So be it.”

Genetics experts have in the past examined the existence of a gay gene.