The Church of Scotland Presbytery of Lewis has raised concerns over teaching on relationship, sexual health and parenthood (RSHP) in the region's schools.
The fears are outlined in a letter to the Comhairle Nan Eilean Siar (Western Isles Council), in which the presbytery says that RSHP material "will confuse and prematurely sexualise young minds".
It goes on to say that "while the removal of homophobic and transphobic bullying from schools is an aspiration Presbytery fully supports", there is the "very real danger that it will be replaced by heterophobic and faithophobic bullying against those who are unable to 'embrace' an ideology that goes against their conscience, morality, and/or faith position."
The presbytery such teaching will make pupil withdrawal from these classes "more likely".
Scottish Government guidance on RSHP says teachers should work closely with parents and carers on lesson content. It also permits parents to withdraw their child "from all or part of a planned programme of lessons" on RSHP.
"If a child is withdrawn, arrangements should be made for them to have alternative positive educational provision," the guidance states.
Other concerns raised in the presbytery's letter are over a single Gaelic translation of the material, which it says will mean less equality of opportunity for Gaelic-speaking families.
The letter was written by Rev Hugh M Stewart, minister of Lochs-in-Bernera and Uig congregations and the Church of Scotland's representative on the Western Isles Council's education committee.
He said: "Following the large volume of parental and teacher concern expressed to the Presbytery about relationship, sexual health and parenthood it feels that the best solution is for the Comhairle to weave its own, distinct policy on relationship, sexual health and parenthood, one that is tailored to meet and reflect the unique cultural, social, linguistic and religious richness to be found across the Western Isles.
"This would ensure the equality of opportunity for children in English medium and Gaelic medium education and avoid the need for pupils to withdraw from classes, eliminating the concerns of parents and teachers."