The project, a longitudinal study of adolescent girls currently in its second year and funded by the NIH, has three major goals. These are: 1) psychological adaptation to pubertal change in terms of timing, rate, and duration of maturational events as well as asynchrony in pubertal growth; 2) the development of eating problems and weight related concerns, especially as they relate to pubertal change; and 3) the goodness of fit between environmental demands and individual adaptation to them as illustrated by the case of delayed puberty in dance and nondance students. The role of endogenous and exogenous variables will be examined for all three goals. Two hundred girls are being followed longitudinally for a two year period. One level are being followed from 5th - 9th grade (Group 1) and 100 from 7th - 11th grade (Group 2). Subjects were drawn from a population known to be at risk for delayed puberty and eating related problems -- private school students. In addition, one quarter of the girls in Group 2 are national ballet dance company school students; dancers exhibit a high incidence of eating problems and delayed puberty. Girls are seen yearly. Pubertal status is measured in terms of height, weight, skinfold thickness, and secondary sexual characteristics. Exogenous variables include peer and family relationships, dating patterns, residential patterns, and maternal attitudes about puberty, weight, and eating. Endogenous variables include temperamental characteristics, body image, feelings about pubertal change, intensity of exercise, and food intake. Psychological adaptation is measured in terms of eating related problems, psychopathology, and depression.