One of my litmus tests for what is established science is that first and foremost, it that it does not change.  The explanation for how computer memory works has been unchanged for over a generation.  This is established science.  The explanation for non-traditional gender roles changes almost by day, with such acronyms as LGBTIQCAPGNGFNBA being the latest flavour of the day.  This is not established science.  It is an evolving set of ideas based on equal parts of science, observation, and politics.  When it comes to sex ed, the school system, particularly at the elementary level, should be focused on established science.  Leave the politics and debate to the grown ups and the specialists.  After all, do we really expect a 6 year old to understand the difference between asexual and gender non-conforming.  Seriously.