"Instead, students are informed that at any age, sexual freedom is a right.
"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.
Aquinas College principal Ray Scott said the programme his staff taught gave students the full story about sex and sexuality.
Schools needed to emphasise the importance of positive relationships as well as teaching students about safe sex, he said.
"The programme that is provided in Catholic schools does provide a pretty clear picture for kids. The relationship side of things is very important."
Mount Maunganui College principal Russell Gordon said he was happy sex education at his school also gave teenagers a full understanding of the issue.
"I'm not an expert but, speaking from our school's context, I would be surprised if students didn't receive a balanced message about sex."
Mr Gordon said students were taught about safe sex but they were also told there was no harm in saying "no".
"A kid needs to be given as much information as possible so that, whatever the choice is, it's informed. That's the whole idea to having sex education."
Sex education is compulsory in New Zealand schools until the end of Year 10. However, parents have the right to withdraw their child.
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.
Shaun Robinson, executive director of the Aids Foundation, said parts of the report were homophobic and unfair.
- Additional reporting Vaimoana Tapaleao
