The Relationship and Sex Education (RSE) proposals have been widely praised for being properly updated for the first time in two decades and preparing young people for the 21st century.
However, some have fears that the new curriculum promotes an agenda.
The new lessons will teach kids about basic relationships (not sex) from the age of four and, among the older years, the Department of Education will introduce teaching on mental health, sexting and female genital mutilation.
RSE is being completely updated for the first time since 2000 and will try to show the link between physical and mental health and cover topics not previously included, such as the influence of social media.
Education Secretary Damian Hinds said: "the internet and social media add new pressures that just weren't there even one generation ago. So many things about the way people interact have changed, and this new world, seamless between online and offline, can be difficult to navigate. Almost twenty years on from the last time guidance on sex education was updated, there is a lot to catch up on."
Explained by Mr Hinds in the House of Commons on Monday, the government have retained the ability of parents to request that their child is withdrawn rfrom these classes.
Any school must respect this 'except in exceptional circumstances' up to three terms before the child reaches 16, at which age the child can decide to opt-in themselves as they will be close to the age of consent.
Antonia Tulley from the Society for the Protection of Unborn Children (SPUC) told Premier Christian Radio's Woman to Woman show she is concerned about the level of influence the proposals give schools: "That is a problem for Christian parents because what has happened is the parents are now put in second place when it comes to this very important issue. The school, the state in effect, is leading the discussion, deciding what your child will learn and when your child will learn it".
"The door is basically being slammed in the face of parents" she said, adding that she felt views not held by everyone were being promoted in the classroom: "We're already seeing there are lots of lesson virtually indoctrinating children about the benefits of same-sex parenting".
Education Secretary Damian Hinds has denied that five-year-old children will be taught about gay and transgender relationships as part of compulsory lessons.
Speaking on ITV's Good Morning Britain on Monday, Mr Hinds said that primary-school pupils will be taught about "respectful relationships" and respect for all kinds of people.
When asked if this included teaching young children about gay and transgender relationships, he said not at that age.
Mr Hinds added: "Nobody is suggesting that there should be these difficult conversations with children at that age, but relationships in the broader sense, friendships, interactions and how you interact with other children and adults. That's very important from a very young age."
Other Christians have broadly welcomed the update, saying it brings the curriculum in line with the modern world.
Gareth Cheesman from the Christian relationships education charity Acet UK told Premier's News Hour: "The general broad strokes of it are very much built around healthy relationships...helping young people to develop the skills to negotiate things like sexual consent and coercion, to understand the impact of the media, to understand body image and the impact of pornography and modern technology - all built on a foundation of value for the individual and healthy relationships".
On the issue of teaching about topics which not all agree on, such as sexuality, Cheeseman said: "Children in primary schools today will have friends who have two mums or two dads as equally they may have friends who only have one parent at home so, at the moment, the guidance is about helping young people to understand the families that they see around them and their peers".
You can listen to the entire interview with Antonia Tully from SPUC here, speaking to Esther Higham:
And the whole interview with Gareth Cheeseman, from the esteem project at Acet UK here:
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