The GTZ supported Reproductive Health Project of Tanzania developed youth-friendly education materials, with basic facts about human physiology and reproduction, sexuality, prevention of unwanted pregnancies and HIV/STIs, as well as about partnership and communication between partners. Based on the most frequently asked questions adolescents had on a range of sexual and reproductive health issues, a multidisciplinary team of specialists together with young people de-veloped six "question-and-answer" booklets. This document is the first one in the serie and deals with 35 questions about growing up, puberty and adolescence. Some of the questions asked are the following : "Why do adolescents start to talk about sexuality and why do they become interested in the opposite sex?", "Why do some people mature early while others become become physically mature late?", "What is sperm?" , "Why do I sometimes get in a very bad mood near my period and what can I do about it?"... All of the questions in this booklet have been collected in recent years by counsellors and researchers working with adolescents. This booklet is meant to provide youths with information on growing up and to guide them in becoming responsible decisions-makers for their own lives. The youth originate from different regions of Tanzania and their ages range from 11 to 20 years. Some questions and answers would need updates. The answers vary on length but all provide clear, precise and unbiased information on the matter concerned.