The ongoing trial on gay marriage in California heard has heard that gay parents raise happy and healthy children.

Cambridge University psychologist Michael Lamb testified that there was no evidence of children faring worse in same-sex headed families compared to those brought up by a man and a woman.

According to Associated Press, Lamb said: “For a significant number of these children, their adjustment would be promoted were their parents able to get married.”

The federal trial is examining whether Proposition 8, which banned gay marriage in California, is constitutional. The case has been brought by two gay couples, one female and one male.

Gay marriage opponents argue that gay couples cannot procreate and that children are best raised by a married man and woman.

Under four hours of cross-examination, Lamb admitted there were differences between the genders, such as men’s inability to breastfeed and the fact that they are more likely to suffer problems such as alcoholism and violent behaviour.

He said there was no evidence to suggest gay couples were more likely to abuse their children but was asked by Judge Vaughn Walker about the epidemic abuse in the Catholic Church.

Lamb said he was not an expert on the matter but contended the issue was a problem with both gay and heterosexual priests.

The trial broke yesterday for the celebration of Martin Luther King’s birthday and resumes today.

Proposition 8 supporter William Tam is expected to testify this week, along with San Diego mayor Jerry Sanders, whose lesbian daughter changed his view on gay marriage.