This study is one of the few to explore Indian students' preferences in methods of implementing sex education and the barriers preventing them from accessing advice about contraception and sexual health.
Exposure to sex education
The findings of this study reported an exposure level of 61.6% of students to sex education lessons at school. This figure is significantly higher than previous literature suggests. McManus et al.'s study in Delhi, conducted in 2007 amongst females of a similar age group, found 47% of students had attended classes about STIs, HIV/AIDS or safe sex . The relatively high level of exposure is unexpected in light of the state's government's objection to the Adolescence Education Programme .
Despite the moderately high exposure of participants to school-based sex education, the proportion of students who believe sex education to be an important part of the school curriculum (86.7%) greatly exceeds those who receive this education. This finding is strongly supported by previous studies which have found that the majority of students and teachers desire formal, school-based sex education [20, 21]. This study suggests that approximately two thirds of students' knowledge regarding contraception and sexual health comes from the school environment. This is contradictory to previous research which suggests that the main sources of information available to adolescents in India about HIV/AIDS, other STIs and safer sex were friends and the media . Whilst friends and the media were the second and third most common sources of knowledge in this study (51.8% and 42.4% respectively), school was the prevailing source.
Given that the vast majority of participating students desire sex education, combined with the fact that for most students schools are the primary source of their knowledge on contraception and sexual health, banning school based sex education may have negative impacts on students' knowledge and ultimately their health. Arguably, there is a need to respond to the collective's desire for sex education. This is further emphasised when considering the high levels of STIs in India, combined with the evidence that the few countries that have successfully decreased national HIV prevalence have achieved this predominantly by encouraging safer sexual behaviours in adolescents .
Implementing sex education
The findings of this study indicate that an overwhelming majority of students' preferred source of advice regarding contraception and sexual health was doctors (63.2%). This supports students' responses that lectures from trained professionals unrelated to the school were the preferred format of delivery of sex education (56.2%). This conflicts with prior literature which suggests that adolescents prefer to consult a relative or friend on reproductive health matters, rather than a health care provider . Students' choice of doctor may suggest that the anonymity and confidentiality afforded by a health care practitioner would enable them to more fully explore this sensitive topic. However, this would not explain why students' choices of consultation with other health care professionals were amongst the least popular (Table 3). The high status attributed to doctors could additionally explain students' choice; students may have felt a higher degree of confidence in consulting a highly ranked professional. Nonetheless, further research is necessary to fully explore this area.
The second most popular response to where students would like to go for advice about contraception and sexual health was friends (36.3%). This may suggest that there is a place for peer-led sex education in schools in India. Whilst peer-led sex education has not been associated with significant improvements in knowledge or behaviour when compared to adult-taught sex education , it has been shown to have a greater effect in changing students' attitudes .
India's society can be considered a conservative one, where sex-related issues might constitute a taboo for discussion . In spite of this there were no non-responders in this study.
However, the results of this study exhibit other societal norms, in particular that of gender differences, which extend to the norms for sexual behaviour (e.g. premarital sex for women is prohibited but is usually condoned or even encouraged for men) . Hindin et al. reported that 32% of men engage in pre-marital sex, compared to just 6% of women in Delhi . The current study illustrates that female adolescents are more limited in accessing advice about contraception and sexual health, with 57.6% of males stating they have good access to advice they need compared to only 39.3% of females. Female participants were almost twice as likely to associate the lack of access to advice with embarrassment compared to males. Furthermore, a significantly higher proportion of girls (72.2%) receive their knowledge about contraception and sexual health from school compared to boys (48.5%). The fact that adolescent girls are twice as susceptible to getting an STI compared to boys  and that they are more dependent on schools for information about sexual health suggests the effect of banning such education may have a differential impact on males and females with significant consequences for female sexual and reproductive health.
This study found that a significantly higher proportion of females obtain information from their parents and other family members compared to male students. This may further demonstrate the societal norm of gender differences. Women are traditionally associated as being the home maker, illustrating that female students might be more at ease seeking information from a family member. Another possibility is that as females are more limited in their access to advice regarding sexual health they have little choice but to seek such information from family members. This further highlights the need for parents to be sensitized to discuss issues pertaining to sexual health, especially with their daughters, as over a quarter of female respondents sought information from their parents.
Moreover, in a country where almost 50% of women are married by 18 and 1 in 6 adolescents are pregnant by the age of 19 , it is not merely sex education lessons concerning STIs and contraception that are important to be delivered to female adolescents, but also lessons in reproductive health and family planning.
A major strength of this study is the high response rate (100%) achieved. However, there are a number of limitations such as social desirability bias, as the questionnaire included questions of a sensitive nature. Subjects may have answered some questions in a manner they felt to be socially appropriate or appropriate to the beliefs of the visiting Western researcher. It is impossible to determine in what direction such a bias would have operated but every attempt was made to reassure participants of anonymity and to conceal participation, therefore minimising the bias. Furthermore, responder bias may have occurred as interviews took place in a school environment and students may have, consequently, over-emphasised the importance of knowledge obtained in schools.
A further limitation of this study is the lack of information available on what form of sex education students had previously received; was it one lecture as part of a science lesson or a series of lectures as part of a sex education programme? Consequently, whilst it was possible to establish the prevalence of students' exposure to sex education in schools, it was not possible to determine the extent of sex education received.
This study has explored an important issue given the robust evidence which suggests that curriculum-based sex education programmes are beneficial in preventing HIV, STIs and early pregnancy in adolescents . However, it is important to note that implementing sex education as a preventative measure in schools in India is limited by school attendance rates. Less than 40% of adolescents in India attend secondary school . Consequently, the poorest sectors, who are most at risk of STIs and teenage pregnancy , are not represented in this study and would not benefit from school-based sex education.
Additionally, it is important to note that this study defined students' education regarding STIs and contraception as being the main component when referring to sex education. However, sex education is a much wider concept than this and future research would be beneficial exploring differing aspects of sex education such as puberty and family welfare.