Posters from No campaigners in the same-sex marriage referendum which say every child has a right to a father and mother have been described as “demeaning” by Tánaiste Joan Burton.

Ms Burton, speaking at the launch of the Labour Party's campaign for a Yes vote, said the poster – from the Mothers and Fathers Matter group – undermined people who were raised in different family situations.

“The notion that people who have been raised in anything other than the kind of perfect family situation that the No people describe, frankly, I find it undermining of people in a way I think is regrettable,” she said. She instanced her own upbringing in an adoptive family.

“I believe a Yes vote is a profoundly good development in our society and our democracy.

“I saw some posters . . . suggesting that this referendum is about surrogacy. The referendum has nothing to do with surrogacy.”

The Coalition's campaign for a Yes vote begins in earnest this week, with Fine Gael launching its campaign today.

Speaking at yesterday's event, Minister for Communications Alex White, Labour's director of elections, said the referendum was "about marriage, not children".

He added: “We can continue to respect the traditional family with children and two parents, one male and one female . . . But I want equality for families, and for children in families, that are different but equally valid.”