I was satisfied that the pursuer did not enter into the arrangement lightly

Sheriff Laura Duncan

The court heard that once the baby was six-weeks-old the couple tried to restrict visits.

They said he was just a sperm donor and wanted legal recognition for the mother's partner.

In a written judgement at Glasgow Sheriff Court, Sheriff Laura Duncan ruled that a lesbian couple cannot constitute a family unit.

She said the child's welfare was of paramount importance in granting the man "full parental rights and responsibilities", because it would be in the baby's best interests to have access to his father.

Same sex couples

The written judgement states that the man was named as father on the birth certificate and he signed the document.

"He is therefore liable for the support of the child", it said.

"The pursuer gave the impression of being a thoughtful individual who considered the long-term implications and issues of what he was about to embark upon.

"I was satisfied that the pursuer did not enter into the arrangement lightly," the sheriff added.

Children need parents who love them and whether that is two parents, three parents or four parents, heterosexual or gay, makes no difference

Ally Jarvis Stonewall Scotland

The sheriff said there should now be a public debate about the parental rights of same-sex couples - and this may ultimately be decided by the Scottish Parliament.

The call for a debate was echoed by gay rights campaigners.

Tim Hopkins of the Edinburgh-based Equality Network said: "I welcome that the sheriff has made it clear that in the case of the father here, the fact that he is gay doesn't stop him from getting full parental responsibilities.

"The law is quite clear that what matters is the welfare of the child but the law needs to be clarified to protect the relationship between the child and the lesbian partner of a mother."

Stonewall Scotland director Ally Jarvis agreed that the judgement was a "positive step".

It should be recognised that children benefit when both their mother and their father have an input into their upbringing

Phil Gallie Tory MSP

"This is part of a wider debate and I would endorse the sheriff in saying that it needs some more serious thought given to it," she said.

"I would like to see a situation where the best interests of the child are at the forefront.

"Children need parents who love them and whether that is two parents, three parents or four parents, heterosexual or gay, makes no difference."

Scottish Tory MSP Phil Gallie also agreed that the ruling was "spot on" - although he did not support a change in the law.

"It should be recognised that children benefit when both their mother and their father have an input into their upbringing," he said.