A Christian family trust has welcomed new government guidelines for relationships, sex and health education (RSHE), but argues they need to be tighter.
Under the proposals expected to be published on Thursday, schools will be told to avoid proactively teaching children about gender identity.
Pupils will not receive sex education until they are nine years old, and contraception, gender identity and abortion will be off the curriculum until children are 13.
Peter Williams, the director of Family Education Trust - a research institute focused on family life - told Premier Christian News he welcomes the guidelines but thinks they need to go further.
"Probably 15 years old is the better limit for a lot of this material - based on the fact that children cannot legally have sex until they are 16."
Williams also raised concerns that the guidance being merely "best practice" rather than statutory could allow "bad actors" within the education sector to ignore it.
Education Secretary Gillian Keegan is making the changes in response to concerns that children are learning about adult issues too early.
Prime Minster Rishi Sunak launched a review into RSHE guidance to investigate whether children were being exposed to "inappropriate content". It followed a call from over 50 Conservative MPs last year, that children were being indoctrinated with "radical ideologies".
According to The Times, teachers are expected to be warned that gender ideology is highly contested and encourage them to focus on the "biological" facts about sex.
Speaking to Premier, Williams says content around gender identity needs to be dealt with in a "purely adult setting. "
"Children have been exposed to various different identities, like furry identities when children believe that they're animals … there can be a kind of social contagion, where people think it's cool to identify as different sexualities.
"Schooling is there for education, it's not there to encourage and enable these identities, which actually may end up being quite harmful. When it comes to gender dysphoria, it can lead you down a path of life-changing surgery and sterilisation.
"This is something which needs to be treated with the greatest possible care."
A school leader's union has argued that age limits on sex education could lead children to seek out information from less reliable sources.
Since September 2020, relationships education has been compulsory for all primary school pupils. RSHE guidance sets out the legal duties for schools to follow.
Under current guidance, covering elements of sex education at primary school level is at the discretion of the school in accordance with the needs of pupils.
Williams has encouraged Christians to help protect children against harmful ideologies by becoming school governors and active in school life.
