Such teenage concerns, often unanswered by school personal, social and health education lessons, are tackled in a book this month.
R U a Teenage Health Freak? has been compiled by Aidan Macfarlane and Ann McPherson, two doctors who wrote the bestselling Diary of a Teenage Health Freak.
The book, produced in the form of an extended problem page, was compiled from more than 8,000 questions asked at the teenagehealthfreak.org website. Queries are organised into themed chapter headings, such as "sex - the ups and downs", "masturbation rules - ok?" and "clued up, not boozed up".
The authors say they aim to tackle common teenage problems by addressing their cause: ignorance. "A lot of people teaching PHSE in schools feel quite embarrassed about discussing these kinds of subjects," said Aidan Macfarlane.
"We're not trying to tread on anyone's toes. We just want to increase the amount of information available for young people. Anything where young people can get information is going to help."
The style is deliberately frank: the authors aim to speak teenagers'
language. Thus, anonymous correspondents are addressed as "dear person with smelly knickers", or "dear headlice owner".
"We've had a lot of girls worrying about being over-hairy," said Dr Macfarlane. "That's a question that I had never been asked."
In a report published earlier this year, the Office for Standards in Education found that sex education was well taught, although there was little opportunity for pupils to discuss relationship questions.
"RU a Teenage Health Freak?" is published by OUP this month, price pound;4.99