The Lawyers' Christian Fellowship has criticised a ruling from the Sheffield Employment Tribunal against the appeal of a Christian magistrate to be granted exemption from ruling over cases that might require him to adopt children to same-sex couples.

Following the ruling, committed Christian magistrate Andrew McClintock will no longer be able to serve on the family panel despite the recognition of the tribunal that he had an "unblemished record" and is "well regarded by fellow magistrates".

In 2004, Mr McClintock approached the chairman of the family panel in Sheffield with his concerns about the potential conflict between his Christian beliefs and the implications of same-sex adoption in the wake of the 2002 Civil Partnerships Act.

Mr McClintock, who believes that children should be placed in households with both a mother and a father, asked that the family panel accommodate his religious conscience and "screen" him from cases which might require him to place children up for adoption in same-sex households.

He also expressed concern that children could be put at risk by the untried social experiment of same-sex adoption in which he said vulnerable children were being used as "guinea pigs".

The employment tribunal rejected Mr McClintock's claim, however, that he had been discriminated against because of his religious beliefs and that his right to religious freedom had been infringed.

Andrea Minichiello Williams, Public Policy Director of the Lawyers' Christian Fellowship, criticised the tribunal's ruling, saying that the case was "a clear picture of how Christian faith is becoming privatised in society".

"It is yet another example of the repression of Christian conscience and signals the prevalence of a secular 'new morality' and the erosion of Christian values at the expense of our children's welfare," she said.

Ms Williams warned of more cases like McClintock's in the future as a greater number of "men and women of integrity - as the court described Mr McClintock - are forced to choose between applying a law which runs contrary to their fundamental Christian belief or obeying their conscience", she said.

She also said that "the imposition of secular values in every aspect of our lives will force those who hold Christian beliefs out of jobs".

"It will be to the detriment of the whole society," she said.

Mr McClintock said, "This ruling is going to make it harder for many conscientious people, whether they are JPs in the family court, or otherwise involved with children, or maybe with different matters of conscience.

"Anyone who holds seriously to the traditional morals and family values of Jews, Christians or Muslims will think twice before taking on such a job," he said.

During Mr McClintock's case, the employment tribunal heard evidence from Professor Dean Byrd, president of the Thrasher Research Fund, and vice president of the National Association for Research and Therapy of Homosexuality (NARTH), the foremost research body in the USA on homosexuality.

Dr Byrd told the tribunal that children raised in homes with both mothers and fathers navigate the developmental stages of life more easily, are more solid and secure in their self and in their sense of gender identity, perform better at school, have fewer social and emotional problems and become better functioning adults.

He also told the court of widely-respected research into the consequences of father or mother absence. While decades of research has shown that parenting families with a mother and father were more financially and emotionally stable, studies on same-sex parenting remains infrequent, he warned, and studies of children raised by male couples are virtually non-existent.

"The expert witness in the case, Professor Byrd from the USA, said there was little research into the effect of same-sex nurture on children's development, and that what had been established was worrying," said Mr McClintock.

"This view of the scientific facts was unchallenged by the other side.

"So, more needy children will be fuelling this experiment in social science, and suffering what the experts call mother-hunger or father-hunger."