Reproductive health outcomes have an impact on both individual and population general health and well-being. Its importance is well-emphasised in the adolescence, which is a transitional phase, characterized by a high grade of vulnerability. In this period, both personality and health-related behavior patterns are formed, which will have an effect on behaviour and health in adulthood. By promoting responsible sexual behavior, opportunity arises for healthy sexual developement and preservation of the reproductive choice. Many countries following depopulation trends have recognized the importance of preserving reproductive ability of the young through longer periods of time, due to delaying the pregnancy to an older age and lowering the average sexual activity initiation age. Sexual behavior like early sexual initiation, having multiple partners, and inconsistent contraception use lead to undesired outcomes, such as sexually transmitted infections, unwanted pregnancies, and long-termed reproductive ability consequences. The average age of sexual initiation in Europe is 17 years; northern European countries report the lowest average age among Europeans, the boys are more likely to initiate earlier, and the gender gap is narrowing. Condom is the most commonly used contraceptional method while the oral hormonal contraception is widely used only in northern and western European region. There is a reported decline in condome use, and the oral hormonal contraception is uncommonly used by the young Croatians (10%). Concurrently, the unsafe contraceptional methods usage is increasing in Croatia. Adolescent pregnancy rates are declining for 20 years; the highest rates are reported amongst eastern European countries and the United Kingdom; the Croatian rate is amongst the lowest reported in Europe. Sexually transmitted infections pose a great challenge because of the high vulnerability of the young, due to special physiological characteristics and certain forms of sexual behavior that makes them more susceptible to acquiring them. Well-timed responsible sexual behavior education, regular preventive examination with counselling and vaccination contribute to preserving the reproductive health of the young.