Surge in teenage sex...
As risky alcohol consumption among Australia's teenagers has gone up so has the incidence of sex "under the influence" and the number of partners, but not condom use.
A survey of Australian year 10 and 12 students has shown a surge in sexual activity over the past decade, and while awareness of HIV/AIDS remained high, so was the rate of risky sexual practices.
"Rates of alcohol consumption among secondary students have increased markedly, as has the proportion of young people engaging in sex while under the influence of alcohol and drugs," said Paul Agius, from Melbourne's La Trobe University.
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"We also found that there is a marked increase in year 12 students having sex with multiple partners."
In 1997, one in five (19.6 per cent) male year 12 students reported having sex with three or more partners in the past year.
When the same question was put to young men in 2008, the figure had almost doubled (38.2 per cent).
For young women in year 12, those who reported three or more partners in the past year also jumped, over the decade, from 12.9 per cent to 27.2 per cent.
Mr Agius said Australia's rate of teenage pregnancy ranked among the highest in the developed world, while sexually transmitted infections among young adults has risen in the past 10 years.
The survey showed students continued to report "high" awareness of HIV/AIDS while awareness of sexually transmitted infections (STIs) also made a small improvement over the decade.
Young women also reported higher overall awareness of the risks of unsafe sex, showing the need for public health campaign targeting young men.
"It is concerning that students appear to be better informed about HIV than either STIs or hepatitis, which are more common," Mr Agius said.
The percentage of young men who reported using a condom for their last sexual encounter remained stable, at 71.1 per cent in 1997 and no improvement in 2008 at 70.9 per cent.
"Although consistent condom use remains moderately high, it is of some concern that condom use has not increased since 1997 despite related increases in sexual activity ... and increased rates of sexually transmitted infections," Mr Agius said.
The research is published in the October edition of the Australian and New Zealand Journal of Public Health.