Co-director of the Children’s Research Centre at Trinity College Dublin, Prof Sheila Greene, said there was no evidence that children in lesbian and gay families were experiencing the kind of problems that some people had predicted.

Prof Greene said: “Children within gay and lesbian families are not any more or less gay, they are not confused and they don’t suffer from mental health problems to any greater or lesser extend than children being reared by a biological mother and father.”

She said debates about who should and should not parent children in Ireland must be informed by scientific evidence rather than unfounded assumptions, and sometimes biased beliefs, about the outcomes for children in lesbian and gay families.

The professor was one of the guest speakers at a national symposium called Marriage Matters for Lesbian and Gay People in Dublin, organised by the National Gay and Lesbian Federation.

She said it was now widely accepted that of the many reasons why children develop emotional or behavioural problems, the sexual orientation of parents did not appear to be one.

But Prof Greene said being raised by lesbian and gay parents was not plain sailing and she urged parents to be aware of the challenges that their children might face.

It was already known from recent Irish research that there was a high level of homophobia and bullying among young people.

“If children are teased because they wear glasses or because their parents were separated, it was reasonable to expect that children may be teased because of the sexual orientation of their parents.

“This will mean that children may have bad moments, like any others, not that they will be psychologically scarred or suffer from mental health problem. The important issue is that parents must be tuned into the needs of their children,” she said.

Meanwhile, well known British-based human rights and gay rights campaigner, Peter Tatchell, said the Irish Government’s proposed civil partnership legislation was a big mistake and an insult to same-sex couples.

“It is a rejection of marriage equality. Separate laws for gay people are not equal laws,” said Mr Tatchell.

The campaigner urged the Irish Government not to go down the same road as Britain with its flawed system of civil partnerships.