Chlamydia bacteria show no obvious symptoms on the genitals
Suffolk health workers are aiming to test 25,000 young people for chlamydia in 2010/11.
An NHS campaign offers free testing kits and 15,000 samples were returned in the county last year.
"Somebody catching chlamydia in their early 20s may find that in their 30s, they're unable to conceive," said Lynda Bradford from NHS Suffolk.
It's estimated 75% of women and 50% of men show no symptoms and are therefore unaware they've got the disease.
The biggest problem of sexually transmitted infection (STI) is for women rather than men. Bacteria infect the ovaries and fallopian tubes and cause scarring.
When scarring occurs the egg can't be released into the womb, thus preventing conception. Scarring can occur in men as well.
"The clear assumption is that if you've had unprotected sex, you should have a chlamydia screen because you can't tell who's got it or who hasn't," said Lynda, who's a senior health improvement manager.
"We recommend that anyone who's under 25 and sexually active has a test every year and when they change their partner as well.
"If you find your partner's been unfaithful, then it's the same as having a new sexual partner.
"Unfortunately, most people don't know when their partner's been unfaithful, so an annual test would pick it up.
"If you're over 25 then and you've had several sexual partners, then we recommend that you go to your GP or sexual health clinics that are run at most hospitals [sometimes called genitourinary medicine (GUM) clinics] and have yourself tested for all sexually transmitted diseases.
"Chlamydia testing isn't targeted for the older group because most people in their 40s are not necessarily concerned about being infertile.
Of the 15,000 tests received last year, NHS Suffolk estimates that 6% (or 1 in 16 people) tested positive and all were treated using simple antibiotics.
Condoms are promoted as providing a barrier to STIs
The feeling among health promotion teams is that the taboo surrounding STIs is getting weaker.
"Schools do a lot of work around personal health and social education," said Lynda. "In classes they talk about sexual health and chlamydia.
"What we have to remember is that there are always new young people coming in all the time, so the campaigns have to continue for the next cohort of 11 and 12 year olds.
"What's quite interesting is a lot of young people think it's just something I do like having my hair cut - it's part of good health and how I look after my body.
"They're not as embarrassed about it as people used to be. They're more concerned about the risks that they've brought upon themselves than the fact they've slept with somebody.
"The stigma of sleeping with more than one person is not there in the way it was 30 or 40 years ago.
"There's always a difficulty with condoms. It's something that people have to carry in their bag.
"There's the embarrassing situation about who's going to put the condom on and am I perceived as being 'more easy' because I have a condom?
"But I think those conversations are much easier for young people than they were. You can buy them in the supermarket - you don't have to go anywhere special.
"What I would say is that being drunk sometimes skews people's view of what is risk."
Lynda Bradford works in the NHS for Suffolk Community Healthcare
New targets for 2010
NHS Suffolk is hoping to try new ways of getting more people to take the chlamydia test including posting kits to some people, particularly young men, when they haven't requested them.
There will also be more outreach work as teams go to where young people hang out and offer tests on-the-spot.
"I wouldn't say treating chlamydia is more important than treating any other STI, but what it does is target young people who have potentially big health problems further down the line.
"The fact that it's symptom-less is a very good reason to promote chlamydia prevention.
"We're on the way to winning the war. In three or four years' time, you'll find most young people will know that routinely we test.
"We're well on the way to raising awareness and making sure that people get a test when they really need it."