"Children have the opportunity to raise questions although questions of a sexual nature are not answered. Parents would be having that type of talk with their children," he said.
A few parents have raised objections to their children taking part in the sex education programme at Lakeview School.
"We inform parents ahead of time and if there are any queries, we talk through the issues. I might have had one or two parents who believe that education should happen at home," he said.
Fraser Mailman, Masterton Intermediate School principal, said sex education at his school "certainly does not delve into those areas" raised in news reports from other regions.
"We keep to a solid framework on puberty and we exercise vigorous teacher discretion where any questions of a sexual nature are concerned," Mr Mailman said.
Sex education lessons are conducted with students who have parental consent to be present and will be delivered next year alongside the Life Education Trust.
"The trust will, keeping within the same factual foundations, inform the kids about biological changes and the abuse of drugs and the changes on the body that can mean as well," he said.
More than 70 per cent of 13,550 New Zealand Herald readers in an online poll said it was inappropriate for 12-year-olds to be learning in class about oral sex.
Only 29 per cent felt sex education was okay and was giving youngsters the information they needed.