ABOUT THE SUBJECT MATTER Adolescence is a time of significant change. The adolescent era spans the interval between childhood and adulthood. It is a time of physical, social, and even emotional upheaval. During this relatively brief period of time not only does physical growth accelerate but, of more significance in the biology of any species, the individual attains reproductive maturity. Within this time frame, the human being acquires the capacity to procreate and perpetuate our species. From a reproductive standpoint, throughout adeolescence the individual is being prepared for perhaps what might be considered the most important function an organism has during his/her brief sojourn on earth, namely to endow successor(s) with a minute quan tity of DNA to enable continuation of its form of life. The interlude be tween childhood and adulthood is not always socially or emotionally sim ple. The anatomic and physiologic modifications that come to pass during adolescence are not necessarily paralleled by a capacity to assume the societal responsibilities associated with reproductive maturity. Although the physiologic changes normally proceed in a predetermined fashion, adaptation to a changing role is a far more trying process. Accustomed to living in a child's world, the subject of adolescent change requires considerable time and understanding to facilitate exis tence in the adult world. The early stages of sexual awareness, for ex ample, are generally extremely confusing and, as evidenced by the in ordinately high frequency of teenage pregnancy and sexually transmitted diseases, can be extraordinarily dangerous."