New ESRI research finds that knowledge of the best method for preventing sexually transmitted infections (STIs) is high among young people, but many of those sexually active do not use condoms

New research, published today (19 February 2025) in two reports by the Economic and Social Research Institute (ESRI), finds that while knowledge of the best method for preventing sexually transmitted infections (STIs) is high among young people, knowledge of fertility is much lower.

Further research finds that peer networks play a significant role in determining the age at which young people first have sex. Young men and women who rely on friends as a source of information about sex, who have larger and more age-diverse friendship networks, and who perceive that most of their friends are having sex, are all more likely to have sex earlier.

The research, funded under a research programme with the Health Service Executive (HSE), draws on data from the ’98 Cohort of the Growing Up in Ireland (GUI) study, collected in 2018 when the young people were 20 years of age. 

Key findings:

The first report ‘Sexual Health Literacy and Sexual Health Behaviours among Young Adults in Ireland’ examined the factors associated with sexual health literacy among young people, and condom and contraception use for those currently having sex:

• Knowledge of the best method for STI prevention is high among young people aged 20 (with over 80 per cent of young men and women correctly identifying condoms).
• Knowledge of fertility (specifically the period during the female menstrual cycle when pregnancy is most likely to occur) is much lower, with just 21 per cent of men, and 37 per cent of women, answering correctly.
• Approximately one-third of young men and women always use condoms when having sex.
• A significant minority (nearly 40 per cent of men, and 32 per cent of women) do not always use either condoms or other forms of contraception when having sex.
• While use of contraception at first sex is high (approximately 90 per cent), a significant proportion of those who are sexually active discontinue contraception use and are not using it currently (nearly 30 per cent of men and just over 20 per cent of women).
• Cognitive skill development (i.e., vocabulary skills at primary level and Leaving Certificate grades) is significantly related to sexual health literacy, especially among women.
• There was little evidence of an association between sexual health literacy and condom and contraception use. Much stronger associations are apparent for factors such as peer culture and relationship status. Being in a relationship is associated with a shift from condoms to other forms of contraception. Those whose peer group at age 17 were sexually active were less likely to use condoms or other forms of contraception, and were more likely to discontinue use over time.

The second report ‘Sexual Initiation and Sexual Health Behaviours among Young Adults in Ireland’ examined the factors associated with the timing, and circumstances, of first sex:

• Just over one-third of males and females first had sex by the age of 17, while a further 50 per cent first had sex before the age of 20. The remaining 15 per cent had not had sex by the age of 20.
• Young men and women who were more reliant on their friends for information about sex were significantly more likely to have sex earlier, as were those who had larger and more diverse (in terms of age composition) peer networks, and peers who themselves were having sex.
• Relying on a teacher as a source of information on sex and relationships was also associated with later sexual initiation.
• Approximately 90 per cent of young men and women used contraception when they first had sex. There was no relationship between age of first sex and contraception use at first sex.
• Young women were significantly more likely to express regret over the timing of first sex than young men (a quarter of young women thought that it had happened ‘too soon’, in contrast to 10 per cent of young men who thought it had happened ‘too soon’). Later age of sexual initiation was associated with a lower probability of perceiving that first sex had occurred ‘too soon’. 

Prof Anne Nolan, one of the authors of the report, commented: “Along with recent rises in STI notifications among young people in Ireland, the findings in relation to condom use highlight the need for renewed public health messaging about the benefits of condoms in preventing both pregnancy and STIs.”

Prof Emer Smyth, one of the authors of the report, commented: “Low levels of fertility knowledge among women and men, which have implications for their future pregnancy planning, point to the need for this issue to be addressed through the revised RSE curriculum, underpinned by ongoing professional development for teachers and supports for parents to engage in conversations about sex with their children.” 

The HSE’s Sexual Health Programme funded this research as part of their work to promote health under the Healthy Ireland Framework. Orla McGowan, Programme Lead of the HSE Sexual Health Programme said: “It is concerning that 20% of women and 30% of men aged 19 and 20 reported not using contraception every time they had sex. This data was collected prior to the introduction of the Free Contraception Scheme in 2022 and previous research identified cost as a barrier to accessing contraception. Almost 2,400 GPs and 2,050 pharmacies are providing services under the scheme and with contraception now free for under 35s, we would expect to see an increase in contraception use among this age group as a result. Further research and data are required to confirm if this is the case.”