John Paul College principal Patrick Walsh said sex education was a difficult and complex subject, however the school's preference was for parents to provide sex education to their children.
"But universally the message appears to be that parents are unwilling or reluctant to talk to their children about sexual health matters, which I think is unfortunate really."
Sex education was included in the school's health curriculum and as the school was a State Integrated Catholic school, there was a strong focus on the church's teachings.
"I think probably [nationally] there isn't as much emphasis on the notion of abstinence. I know it might be an old fashioned concept, but in fact I think it is still very relevant today.
"It seems to be an admission that children are going to have sex and therefore the default position is 'let's give them contraceptives'."
There instead needed to be more focus on abstinence first, Mr Walsh said.
Mr Walsh was happy with the school's sex education programme and very few children had been opted out by parents.
Dr Grossman said while most of the resources claimed to promote sexual health, they offered little encouragement of restraint or self-discipline.
"Sex is seen as risky only when it's unprotected. The efficacy of condoms is overstated - in some cases, vastly so. Young people are led to believe that sex is easily divorced from emotional attachment."
Dr Grossman has regularly spoken about sex education in America, but has come under fire for her strongly conservative views and church affiliations.
During a visit to New Zealand last year, Dr Grossman said sex education should present the "ideal" - one sexual partnership for life, delayed until adulthood.
Sex education is compulsory in New Zealand schools up until the end of Year 10. However, parents have the right to withdraw their child.
In the early years children learn about body parts, and identifying gender differences. Then, from late primary onwards they learn about the physical and emotional development of puberty, and about reproduction and sexual behaviour.
Family First director Bob McCoskrie referred to cases where 14-year-old girls were taught how to put condoms on plastic penises, and a female teacher imitated the noises she made during orgasm to her class of 15 year olds.
The report's release follows publicity last week about an 11-year-old Auckland boy who fathered a child after having sex with his best friend's 36-year-old mother. additional reporting Vaimoana Tapaleao