Jennifer Schultz didn't hesitate when she was asked to sign the permission slip for her 15-year-old daughter, Chloe, to attend an excursion organised by her school, Gymea Technology High.

The Synergy Schools Conference was billed as a one-day event in August for year 9 students with topics that "include leadership, mental health, media and creativity in music and dance".

So Ms Schultz was concerned when Chloe returned from the excursion "confused" by a sex education seminar that had been delivered at the conference.

Her concern turned to anger when she discovered the conference was owned and run by the local Shirelive church - a member of the evangelical Australian Christian Churches group.