Young adults in this country have some of the highest rates of Sexually Transmitted Infections (STIs) in Europe – and they're going up. Around one in ten under 25s are infected with chlamydia, the most common STI in the UK.

Lots of people mistakenly think that if they know someone, or if that person takes care of their appearance, then that person won't be carrying an STI. It would be great if you could tell from just looking – but you can't.

When you have sex with someone you plug into a network of all their partners and all their partners' partners. If any one of them is carrying an STI, you're at risk – so if you have ever had sex without a condom the odds aren't in your favour.

Have you got any unusual symptoms? Are you worried about an unsafe sexual encounter? Then have a go at the online test below to see how at risk you are.

For information on STIs and condoms visit www.condomessentialwear.co.uk

Alternatively call the national sexual health helpline free of charge on 0800 567 123 for confidential advice.

If you are under 16 and would like further information on sex and relationships, go to www.ruthinking.co.uk

For the third year running, MTV UK have partnered up with Durex for Bare All 2009, which aims to encourage young people to talk openly and honestly about sex, and to take control of their sex lives by always using a condom.

MTV's Sex Degrees of Separation explores some of the most infamous celebrity relationship chains and links them back to you. Could you have shared a sexual partner with a celebrity?

On-hand to share their experiences and impart advice are the Sugababes, Florence and the Machine, Tim Westwood, Danielle Lloyd and Calum Best, who candidly discuss everything from losing their virginity and sexuality to unintended pregnancies and celebrity role models.

We will also take a no-holds-barred look at sexual relationships between a group of eight friends, tracing back their sexual history to see who they're linked to within their group. A few surprises are revealed along the way, prompting a visit to the clinic to get tested for infections.

Don’t risk it, use a condom. Even with a celebrity.