Reproductive health is a crucial component of general health during adolescence and adulthood as the severity of problems faced during the time of puberty decides the health of next generation as well as the health of both males and females beyond reproductive years. A majority of young teenagers are still far from access of education on sexual and reproductive health and rights. This study attempts to understand the knowledge and perceptions of school-going adolescents regarding pubertal changes, pregnancy, abortion, menstruation (girls only), masturbation (boys only) and problems of reproductive health. A cross-sectional study was conducted in the urban area of Aligarh city of U.P. (India). It consists of 650 boys and 1022 girls of 9th and 11th standard of both Hindi and English medium schools. Both boys and girls are interviewed by a self-administered structured questionnaire maintaining high level of confidentiality. Adolescents of Hindi medium schools are more ignorant regarding sexual health than those of English medium schools. The majority of boys (65.8%) gather information on sex from internet websites and also by watching blue movies. Over two-third girls discuss their personal problems with their parents. Around one-fourth of boys have ever involved in sexual intercourse. Mean age at first intercourse is found to be 15.43 years and 14.95 years for boys and girls respectively, who were ever involved in sexual intercourse. Only 16.4% Hindi medium school boys know that father is responsible for the determination of gender of the child. Merely 60% girls have the knowledge about menstruation before it started and in most cases mothers give this information to their daughters.