That earlier draft guidance had suggested sex education should not be taught before Year 5, while topics like sexual harassment and pornography should not be taught before Year 7.
Instead, the government will outline areas that should be introduced in primary school and what students should know by the end of secondary school. This final draft is due to be published later on Tuesday.
The Department for Education (DfE) says this approach will ensure that children are not taught content they are too young to understand - without assigning specific ages to individual topics.
But the shadow education secretary, Laura Trott, says age limits must be put in place, adding that the guidance "weakens key safeguards" by "scrapping protections that prevented under-nines being taught about sex".
Parents will have the right to view all of their school's RSHE curriculum materials, a move welcomed by the charity Parentkind.
Frank Young, from the charity, says it's important that teachers consult with parents first to understand what is age-appropriate for their child "so that we put parents in the driving seat".
The new guidance, which schools will begin implementing this autumn, will come into full legal force from September 2026.
It will require primary schools to teach respectful relationships, boundaries and the risks of sharing information and images online.
It is also expected to recommend that conception, birth and puberty is taught in Year 5 or Year 6 - but this will not be compulsory.
Under the new guidance, primary school teachers may also choose to discuss the sharing of naked images or online sexual content if it is affecting their pupils, or if they know that students have seen pornography.
By the end of secondary school, students should be taught how to keep themselves and others safe, including how to avoid sexually transmitted infections and unplanned pregnancies.
Additions in the secondary school curriculum are expected to include lessons on:
