More Irish teenagers are having sex from as young as 14, and are at risk of contracting sexually transmitted infections (STIs), according to a new report.

The majority of teens become sexually active at 17 — but the past five years has seen a growing number of 14 to 15-year-olds becoming sexually active, the report claims.

However, the incidence of STIs among Irish teenagers in Ireland is still less than a quarter of the rate in Britain.

The study was carried out by drug company Pfizer as part of a Way2go series aimed at highlighting issues relating to young people.

Speaking yesterday at the launch of the report, Dr Jack Lambert, an expert in infectious diseases, said that while official figures show that the number of STDs reported for all ages trebled between 1995 and 2006, the annual figure of 12,000 could be as high as 120,000.

Many people with STDs exhibit no symptoms and can pass the disease on to other people. It could be 10 to 20 years before someone who is HIV-positive shows up with complications like brain abscesses.

Dr Lambert said that around 10-20pc of sexually active people are estimated to be carriers of the disease chlamydia, which can result in infertility or ectopic pregnancy in women.

Other findings from the research, which involved interviews with 18- to 20-year-olds and parents of 14 to 16-year-olds, showed:

* Most youngsters rely on subjective judgment when deciding if their partner is “safe”.

* Very few parents raise the subject of STIs with their children and have a low level of knowledge about them.

* Many parents take the role of silent witness, leaving the task of sex education to schools.

* Others prefer to take the role of blind witness — they would rather not know that their child is having sex as long as they are using contraception.

* Many teenagers actively try to avoid discussions with their parents about sex, pretending to be disinterested or claiming to be already informed.