A range of studies has shown that the welfare of children is not adversely affected through being raised by a lesbian mothers or by two lesbian parents, the High Court was told yesterday.
Prof Richard Green, a US psychiatrist and expert on gender identity, rejected suggestions by State counsel that it was "premature" to conclude from existing studies as to the long-term development of children raised by lesbians or that the methodology used in such studies was flawed.
A large body of data shows that children in lesbian families were doing "very well" and he was not aware of any study that showed children were worse off in welfare terms if raised by a lesbian couple rather than a heterosexual couple, he said.
He agreed that several studies to which he referred featured 2,000-3,000 children and only one of those was a longitudinal study, which followed children from a very young age to an average age of about 25.
While the other studies were cross-sectional and focused on the position of children at earlier stages, they were also of value. All the studies tended to confirm earlier research dating back 30 years indicating that the welfare of children or their sexual identity was not adversely affected through being raised by a lesbian mother or by a lesbian couple.
Most of the literature to date was persuasive in showing there was no difference in the development of children raised by lesbians, he said. There was little research into how children's welfare was affected through being raised by homosexual males, he added.
The quality of the parenting, not the sexual identity, was the essential ingredient of effective parenting and the best interests of the child, Prof Green said.
He was giving evidence by video link from Britain where he is research director at the gender identity clinic at Charing Cross Hospital, London, in the action by Dr Katherine Zappone and Dr Ann Louise Gilligan to have their 2003 Canadian marriage in recognised as valid by the State authorities here. Alternatively, they say they are entitled to marry in Ireland.
The action is against the Revenue Commissioners and the State who deny that the refusal to recognise the validity of the couple's marriage breaches their rights under the Constitution and the European Convention on Human Rights.
Evidence on their behalf concluded before Ms Justice Elizabeth Dunne yesterday. The case resumes on Tuesday when the State will begin its evidence.
Prof Green yesterday said one study began assessing children of lesbian mothers and heterosexual mothers in the mid-1970s when the children were about 10. They were reassessed in 1991-92, when they were 25.
It reported that children from the lesbian mother families reported more positive relationships with their mothers' female partners, both as adults and during adolescence, than the comparison group whose mothers had male partners. There was a small tendency among the children to remember being teased about their own sexuality, particularly for boys. Twenty-three of the 25 children were heterosexual.
Prof Green told Paul Gallagher SC, for the State, he was not aware of a paper suggesting that given the nature of studies on lesbian parenting to date, it was premature to draw conclusions relating to the welfare of children in such situations. He agreed that if the methodology of a study was seriously flawed, the conclusions could be questioned.
