The father of a 12-year-old boy is questioning why his son has been taught "all the grubby stuff" about sex, but none of the basics, such as how a baby is made.
The man, who is in his 40s, took his son out of sex education classes last week because of how explicit they had been.
The boy's class had discussed things they could do besides intercourse, and the teacher had suggested oral sex as it "wasn't sex" and "won't inevitably lead to sexual intercourse".
Anal sex was discussed as another option.
Students also lay on the floor together with their eyes shut imagining the world was predominantly gay.
The father said his son was too young to be given such graphic sex education and had come home upset.
"He just thinks it's disgusting. You can hardly label a 12-year-old who has not reached puberty and probably thinks girls are yuck anyway prudish for thinking these things are disgusting.
"It's just been dumped in his lap with no delicacy."
The father had spoken to his son's teacher, who confirmed what had been taught in class, and now planned to meet the school's principal this week.
He signed a consent form for his son to be in the class, but he believes many parents are unaware of the explicit nature of what is being taught.
"I certainly think that what we are discussing now in terms of the explicit content is age-inappropriate.
"How about teaching kids about relationships before oral sex and anal sex and the clitoris, then see whether we have more luck with kids respecting each other ... We have just completely abandoned it."