A landmark study of Australian high school students' sexual habits has revealed ''sexting'' online and via mobile phone is so widespread experts are urging parents to accept it as a form of ''modern day courtship''.
The La Trobe University study shows more than 70 per cent of sexually active year 10 to 12 students have sent explicit text messages, 84 per cent have received them and more than half have sent naked or semi-nude photos or videos of themselves.
Despite fears the increasing use of technology is encouraging early promiscuity, the report reveals the rate of intercourse is actually dropping as more teens choose to wait.
Conducted every four to five years, and considered the most accurate snapshot of youth sexual behaviour, the fifth National Survey of Australian Secondary Students and Sexual Health found 23 per cent of year 10 students and 50 per cent of year 12s have had sex, compared with 27 per cent and 56 per cent, respectively, in the 2008 poll.
Almost 70 per cent cent are sexually active in some way - having experienced oral sex, deep kissing or genital touching - down from 78 per cent in the last survey.
Released before Sunday's launch in Melbourne, the 2013 survey - involving more than 2100 students from 436 government, Catholic and independent schools across Australia - for the first time looked at the way teenagers are interacting sexually online.
Commissioned by the federal Department of Health and used to inform sexual health policy, it shows almost 90 per cent of 16 to 18-year-olds use social media such as Facebook, Twitter or Instagram every day, with one in five saying they use the sites for sexual purposes.
Some 54 per cent of all those surveyed have received sexually explicit written text messages, 42 per cent have received explicit, nude or nearly nude photos or videos and 25 per cent have sent such images or videos. Among sexually active students, more than 66 per cent are engaging in sexting.
Lead author Anne Mitchell, who has conducted the study since 1992, urged caution, saying that despite fears a sexualised, digital culture was increasing pressure on young people to have sex before they were ready, the proportion having unwanted sex last year - due to pressure from partners, friends or being frightened or drunk - had fallen from 32 per cent in 2008 to 25 per cent.
''Despite the advent of this technology, sexual activity has remained fairly stable over the past two decades,'' said Professor Mitchell, of the Australian Research Centre in Sex, Health and Society at La Trobe University. ''It's a social, online world kids live in and sending these images and messages is part of their sexual relationships so it's really a new form of courtship.
''It appears to be happening universally and, while we need to be aware of the harm that can come if those messages are sent out far and wide or misused, it doesn't appear to be doing harm for the majority of kids … Parents need to stop panicking about the use of technology and trust their kids - talk to them about their relationships, treating others well, having the kind of sex they want and being safe.''
More than 70 per cent of those surveyed who had sex had no regrets, while 54 per cent of those who were not sexually active were ''proud to say no''.
Teenagers who had three or more sexual partners fell from 30 per cent in 2008 to 23 per cent in 2013, while 55 per cent of those having sex were in a relationship.
Although 17 per cent of young people were drunk the last time they had sex, overall 40 per cent had never drunk alcohol, up from 21 per cent in the 2008 survey.