One in four sexually active young people in the UK fails to use any form of contraception with a new partner, a survey has revealed.
The figure prompted health campaigners to call on the Government to give sex and relationships education in all schools a higher priority.
Personal hygiene was rated as the most important consideration - ahead of contraception - when preparing for a date that could lead to sex, the survey said.
The worldwide survey, which included young Britons, was carried out by Marie Stopes International for World Contraception Day on September 26.
The UK results revealed 16% of young people who admitted to unprotected sex said they did not use contraception with a new partner as they forgot, 13% said their partner preferred not to use contraception and 19% said they had been drunk and forgot.
Confusion and a lack of information about contraception was apparent with almost half of all respondents saying they were not very familiar with or were confused about the different types of contraception.
The survey revealed 32% of young people in the UK said they sometimes feel a little confused about the different contraception options and do not know which method is best for them and their partner. And 19% of young people in the UK believe the "withdrawal method" is an effective form of contraception.
A total of 31% of young people have a close friend or family member who has had an unplanned pregnancy.
The organisation said there was also a "head in the sand" approach to sexually transmitted infections with one in three people saying if their partner was thought to have an STI it was up to their partner to seek a diagnosis and information - even though they themselves could be infected.
The research was part of a worldwide survey of 5,223 respondents and was funded by Bayer Healthcare. A total of 206 British under 24-year-olds (100 male and 106 female) responded to the questions carried out via online interviews in May 2010.