The mean age of first sexual initiation (17.07) in this study is slightly higher than previous studies done in Dessie, north east Ethiopia (16.8 years), in Kolladiba, north west Ethiopia (15 years), in Gojam, north west Ethiopia (13.5 years) and in Butajira, southern Ethiopia (16 years) [11, 17–19]. The difference may be explained by the decrease in early marriage which was the main reason for early sexual initiation in rural youths [5, 6, 11, 17]. Another explanation might be AIDS-related campaigns to delay first sexual intercourse might have had an inhibiting effect [5, 6, 16].
Early entry to sexual initiation has very important implications for the sexual and reproductive health of youths. In this study alcohol users were almost four times more at risk to initiate sexual intercourse earlier than those who didn’t use alcohol and this is in line with studies done in other parts of Ethiopia [15, 17]. This is true even despite the concern about HIV infection, because alcohol decreases self control and sexual negotiation skill of adolescents [11, 13]. Youths who chewed khat were also found to be seven times more likely to initiate sexual intercourse earlier than their counterparts. This finding is also supported by similar studies in other parts of Ethiopia [11, 15, 17]. The possible explanation for this association could be due to loss of track of mind induced by khat chewing. During the hypo manic phase, chewers may not be capable of rational judgment and they also may not be able to predict the serious consequences of their actions [13, 15]. Thus, the chewers could walk into the most dangerous situations feeling that there is no danger and being unaware of the possible dangers to their lives or well-being, they get motivated to have casual and early sexual initiation [13–15].
This study also indicated that unemployed youths were almost seven times more at risk to practice early sexual initiation than those who are employed. The higher risk of early sexual initiation among unemployed youths in our study raises our suspicion of the use of alcohol and khat by unemployed youths which predisposed them to have early sexual initiation. This possible explanation is supported by a study in Ethiopia in which the most frequent substance abusers were jobless youths and street children .
Youths with no comprehensive knowledge on HIV were found to be eight times more likely to practice early sexual initiation than those who have comprehensive knowledge on HIV and this could be due to the fact that youths who do not have comprehensive knowledge on HIV may fail to appreciate the importance of delay of sexual intercourse for prevention HIV infection or may have less access to sexual and reproductive health education and promotion in general. This is in line with the research finding from Nigeria where youths with poor knowledge on HIV initiated sex earlier compared to youths with good knowledge on HIV  and another study among Flemish secondary school students reported similar finding .
However viewing pornographic materials were not associated with early sexual initiation in this study which contrasts with the result of a study among college students in Korea where youths having pornography experience were at higher risk of initiating sex than their counterparts . This might be due to few numbers of respondents who acknowledged exposure to pornographic materials in our study populations. The possible explanation for this could be under-reporting of exposure to pornographic materials because of cultural issues or could be due to recall bias.
Social desirability bias is a potential limitation of this study. Another limitation is the use of cross sectional data and this makes it difficult to establish causality. The study is also health facility based and therefore precludes generalization to all youths in Ethiopia. Despite these limitations, the study provides useful information that will inform health service planners to design a strategy for delaying age at first sex and for the prevention of HIV in Ethiopia.