Rishi Sunak has ordered an urgent review into sex education in schools following reports of "age inappropriate" materials being used in some lessons.
Miriam Cates, MP for Penistone and Stockbridge, has led the campaign for an independent inquiry, writing to the PM to raise concerns about sexually graphic content and the promotion of gender ideology in schools.
Her letter was supported by nearly 50 Conservative MPs, including former home secretary Priti Patel.
Addressing the Commons on Wednesday, Mrs Cates raised concerns about the lack of regulation of resources currently being used in schools.
"Graphic lessons on oral sex, how to choke your partner safely, and 72 genders. This is what passes for relationships and sex education in British schools," she said.
"Across the country, children are being subjected to lessons that are age inappropriate, extreme, sexualising and inaccurate, often using resources from unregulated organisations that are actively campaigning to undermine parents.
"This is not a victory for equality. It is a catastrophe for childhood."
Mr Sunak said he has instructed the Department for Education to "ensure that schools are not teaching inappropriate or contested content in RSHE [relationships, sex and health education]".
"Our priority should always be the safety and wellbeing of children and schools should also make curriculum content and materials available to parents," he said.
"As a result of all of this, we are bringing forward a review of RSHE statutory guidance and we will start our consultation as soon as possible."
The Safe Schools Alliance said that some of the materials it has seen are "appalling" while others "verge on being a criminal offence".
Reacting to news of the review, the Safe Schools Alliance said that those responsible should resign over the scandal.
"The Conservatives have failed to govern and Labour have failed to oppose," it said.
"Huge amounts of children have been damaged by a widespread failure of safeguarding. This is completely unacceptable and lots of people need to resign."
Transgender Trend said, "We've been documenting ideological sex education materials for some time and welcome Miriam Cates' initiative."
The Telegraph reported last week that a drag queen invited to an Isle of Man school told 13-year-old pupils that there are 73 genders.
The newspaper also found evidence of children as young as 12 being asked their opinions about oral and anal sex.
Eliza Cox, vice-chairman of Marown Commissioners, told the Energy FM Isle of Man radio station that she had heard of a teacher on the island being told to teach Year 7 and 8 pupils how to masturbate.
Amanda Spielman, chief inspector of school regulator Ofsted, told The Telegraph: "It's clear that there are materials being used which have no basis in any reputable scientific, biological explanation or any properly grounded understanding of human relationships."
