Christians are being asked to pray after another delay to the publication of new guidance on transgenderism in schools.
The Christian Institute said the continued delays were putting more children at risk of harmful transgender ideology and leaving the fight to students, parents, teachers and school governors.
"It is clear that there are political battles going on behind the scenes between those who want to put an end to this scandal and those who do not. There is a great deal at stake," said The Christian Institute's Ciarán Kelly.
New transgender guidance for schools in England was due to be published by the summer but is now expected in the autumn.
It will advise schools on how they should treat children who want to 'socially transition', including whether they should be referred to by different names and pronouns.
It was reported in the media this week that the government has pushed back the release of the guidance after the Attorney General for England and Wales advised that an outright ban on social transition in schools may be unlawful and that new legislation may have to be passed.
"Transgender guidance for schools in England has been delayed again ... In its absence, hundreds more children are at risk of joining those who have already been harmed by transgender ideology being taught as if it were fact," said Kelly.
"Many bitterly regret having been duped. Students, parents, teachers and governors alike will have to continue to fight to uphold the reality of biological sex."
Earlier this week, Andrea Williams, head of Christian Concern, voiced disappointment at the delay.
"No new laws are needed to tell schools to call boys 'boys' and girls 'girls'," she said.
"Children can't change sex. They can't change legal sex, and they can't change biological sex. Why is it so hard for the government to tell schools this simple fact?
"Schools enabling young children to socially transition is a major safeguarding issue. It is harmful for the children and all the pupils in the class. There is no excuse for the government continuing to allow this harmful unscientific practice."
