Negative Side: Tv shows
Tv in genral represents Teenagers in quite a negative way, for example tv shows such as Skins which is a quite commonly watched tv show, Have drugs, sex, and viloence in them.
http://www.e4.com/skins/
Negative side: BBC News
On 4th june 2012 bbc news wrote an article on teenage pregnancy the title was 'London teen pregnancies hit record low'
NHS has quoted 'Free condoms have helped teenage pregnancies in the capital reach a record low, NHS London has said' and also said in the same article
"In the last year more than 50,000 condoms have been handed out across the capital," NHS London said. and, The number of pregnancies among under-18s fell from 1,158 in the same period in 2010.
http://www.bbc.co.uk/news/uk-england-london-18321569
Postive side: Tv show
Glee is quite a postive representation of teenagers because firstly they all attend school, and it shows diversity and a range of diffrent characters which all have diffrent personalities.
Negative side: Films (Easy A)
Is about a clean-cut high school student relies on the school's rumor mill to advance her social and financial standing. Also in the film the main character 'Olive' agrees to fake a tryst with her openly gay classmate so people will think he’s straight and stop picking on him. Once again word spreads that she’s “easy,” and she starts making a business out of faking sex for the sake of others, while ruining her reputation in the process.

Negative side/postive: BBC News (2010)
Michelle Roberts wrote un article on under-18 ban cut smoking rates and said Teenage smoking rates in England have dropped since the legal age for buying cigarettes rose from 16 to 18, research by University College London suggests.
He found out that
Researchers surveyed more than 1,000 teenagers aged 16 and 17 before and after the age rise in October 2007.
Smoking rates in this age group dropped significantly, from 24% before the law change to about 17% after it. Smoking rates in over 18s remained unchanged.
http://www.bbc.co.uk/news/health-11001599