New research has found widespread concern among parents about the content of relationships and sex education (RSE) lessons.
Nearly half of parents (46%) feel some form of concern about what their children are being taught in RSE.
Among parents who had requested to view the RSE materials being taught to their children, nearly half (44%) said these requests had been denied.
Over a third (36%) of parents said they had never been consulted on the content of their child's RSE curriculum, despite this being a statutory requirement.
Over half of parents (52%) were not confident that their child would be able to express opinions contradicting RSE materials without being judged.
Two in five parents (41%) said their school was using materials from third-party in RSE lessons.
The poll was carried out by Savanta on behalf of Christian charity CARE, and involved 1,001 parents in England with primary or secondary school children.
It was carried out as the UK government continues to consult on statutory guidance for schools in England.
Jack Lawther, Policy Officer at CARE, expressed concern about reports of "contested and inappropriate content" in RSE lessons.
He called on the government to ensure that schools are complying with their statutory duties and "respecting parents' role as the primary educators of their children and championing an environment where children and young people can share their views."
"Our polling, coupled with separate reports, demonstrates that many parents are in the dark about what's being taught, and concerned about what their children might be being exposed to," he said.
"It also suggests that more than three million children are receiving teaching on sex and relationships from unregulated, third-party organisations.
"It is very important that parents have access to sex education materials taught to their children, and schools have a legal duty to ensure that parents are consulted on the content of lessons.
"We'd also stress the importance of allowing children to voice their opinions and share any concerns they have about teaching materials."
