Gay rights campaigners and adoption groups have been angered by the Catholic church in Scotland’s plans to seek an exemption from allowing gay couples to adopt.

Senior Bishops are seeking a “conscience clause” giving the church and other faith-based groups the right to reject applicants to their adoption agencies on the basis of gender.

They fear Catholic-run adoption societies will be challenged under new laws expected to come into force next year. The Times revealed talks have been held privately with the Scottish executive in an attempt to reach a compromise

Calum Irving, director of Stonewall Scotland, the gay rights campaign group, told The Times: “We would have an issue with anyone providing an adoption service which specifically excluded same-sex couples.”

“The Catholic church is continually asking for its belief system to be imposed on the rest of Scottish society and I hope that the executive legislates in a non-discriminatory way. Granting the Catholic church exemptions is a slippery slope.”

Church figures believe the sanctity of heterosexual marriage is under threat and claim that the effects on children of being raised by a gay couple are not fully understood.

“If the proposals go ahead as they stand, the bishops would certainly expect an exemption for faith-based adoption agencies,” said the Right Rev John Cunningham, Bishop of Galloway and chair of the national committee for pastoral and social care.

“We are disappointed that the executive do not seem to have recognised the unique contribution that a stable married couple can make to the upbringing of children.

Government ministers insist the shake-up in adoption laws is needed to widen the number of people eligible to adopt the growing numbers of children in temporary foster care. Last year there were 3,468 children in foster care – the highest total for 20 years. Yet since the 1980s the adoption rate in Scotland has fallen from 1,000 a year to under 400.

At present one person in an unmarried couple can adopt, with the other applying for a residency order. The new law will grant both of them equal parental rights and give same- sex couples the opportunity to adopt. Similar rights are already enjoyed south of the border.

Barbara Hudson, director of the British Association for Adoption and Fostering (Scotland), said: “We understand the Catholic church’s position but regret that at a time when there is such a need for new parents, that not all agencies are united in a common message. Peoples’ sexual orientation should not be a factor.”