Forbes magazine has apologised to Ireland’s president after stating incorrectly that he’s gay.

The US financial publication described Michael D Higgins, who’s been married to his wife Sabina for almost 40 years, as an “acknowledged homosexual” in an online article.

Cork-based journalist David Monagan said it’s the worst mistake of his career and has apologised to the Higgins family.

“I made a terrible mistake and I apologise to Michael D Higgins who I have respect for,” he said.

“I feel horrible. The story is that I made a mistake, for which I apologise from my heart. It was under deadline pressure and is inexcusable.”

The Irish Independent reports it took a number of hours for Forbes to realise the mistake.

At an LGBT youth event last March President Higgins spoke of the need to challenge homophobia in Irish society. 

He said: “We have to ask about how racism gets going, how homophobia does its destructive work, how isolation tears at a person’s wanting to exist, how important every person is. These are important issues, not merely emotional issues.”

In June, Deputy Prime Minister Eamon Gilmore called for greater tolerance in the country. 

A referendum on equal marriage in Ireland will take place in 2014.