OP if you're in England, then this link Amy be helpful eg:
"You will need to decide the outline of your curriculum and consult with parents and carers on the policy before finalising it."
"Schools are required to teach:
• relationships education (all primary aged pupils)"
"Sex education at primary school is not compulsory but can be taught if a school decides that it is appropriate to do so.
All pupils should receive teaching on lesbian, gay, bisexual and transgender (LGBT) relationships during their school years. Secondary schools should include LGBT content in their teaching. Primary schools are strongly encouraged, and enabled, when teaching about different types of family, to include families with same sex parents."
"The statutory guidance suggests typical sections you may wish to include in your policy such as:
• details of the content or scheme of work and when each topic is taught, taking the age of pupils into account
• who delivers relationships education or relationships and sex education
• whether you’re using any external organisations to teach part of the curriculum
• how the policy has been produced, and how it will be kept under review, in both cases working with parents and carers, as set out in the advice on engaging parents with relationships educationn_"
www.gov.uk/guidance/plan-your-relationships-sex-and-health-curriculum
So you need to know what they're teaching, they aren't required to teach sex ed or trans topics at primary, and they're encouraged to include families with same-sex parents at primary. There's also a section on using external providers.