The purpose of this survey study was to examine the sexual risk behaviour found among female students at vocational schools and to compare these behaviours among the first, second and the third year students in vocational schools. Using multistage random sampling, 497 students were selected from the 1st-3rd years in vocational schools in Songkhla and Pattalung provinces. The content validity for sexual risk behaviour in the prevention aspect tested using Cronbach's alpha was 0.87. Knowledge of the prevention of both sexually transmitted diseases and pregnancy were tested with Kuder-Richardson formula and it was 0.91. Descriptive statistics and one-way ANOVA test were used for data analysis. The results were as follows:
1. Nine point three percent of the sample had an initial sexual relationship between 12-19 years of age and usually with their lover (89.1%). The characteristic of sexual behaviour was oral sex (30.4%) and lesbian (26.1%). On both the first occasion and subsequent sexual relationships birth control was used in 19.6% and 28.3% respectively. When they had problems of a sexual nature they mostly consulted their friends.
2. Aspects of prevention for sexual risk behaviour found that most respondents did not use any form of protection and only 37.8% used a condom correctly every time. Peer groups had the highest influence on sexual risk behaviour usually after they had been drinking alcohol and then they had sex. In the study sample media sources, such as Internet web sites and VCDs, were found to be important stimulants of sexual desire (62%, 56.3% respectively).
3. In relation to the knowledge for either the prevention of sexually transmitted diseases or pregnancy, most respondents did not know the best contraceptive method to use: contraceptive pills, condoms or drugs.
4. Adolescents with different levels of education displayed significantly different sexual risk behaviours (p < .001). The first year student's sexual behaviour had a higher risk than did the second and the third year students (p < .001). The second and the third year students showed no difference.
The results of this study have suggested that to reduce the risks from sexual behaviour among adolescents knowledge of “safe sex” should be promoted. Education concerning attitude towards sex and sexual values should also be taken into consideration in order that adolescents can protect themselves against sexual risk behaviours.