Puberty is the process of becoming sexually mature and it has fundamental somatic and psychosocial implications. The focus of this dissertation is on the short- and long-term developmental significance, concerning soma et psyche, of female pubertal timing. Four studies were designed and performed to accomplish these aims. Six samples of different ages from different countries and at different time points, comprising several thousand females, some of whom were followed longitudinally, were used. Age at menarche was used as the measure of pubertal maturation. The first main aim of this dissertation was to explore the mechanisms that might explain the well-established link between female pubertal timing and problem behavior and to identify the contextual conditions under which associations are stronger or weaker. Existing explanations are unsatisfactory, and little is known about conditions that might affect the strength of the associations. 

For Paper I, we tested and confirmed a peer socialization hypothesis as a satisfactory explanation for the link between early puberty and problematic adjustment. In short, this hypothesis posits that early-developing girls associate with older peers and boyfriends because they feel more mature than their same-age peers and – through these peers and boyfriends – are channeled into more socially advanced behaviors, including problem behavior. This should be particularly true in contexts where heterosexual relationships are sanctioned and where there is an abundance of deviant youth. For Paper II, I used a biopsychosocial approach, and investigated pubertal timing along with self-perceptions of maturity and early romantic relationships. The findings revealed that early puberty had very different implications depending on the psychological and social contexts in which it was embedded. For instance, when early puberty was coupled with feeling mature and having early romantic relationships, it was associated with adjustment problems. When early puberty was coupled with neither, it was not linked to particularly high levels of problem behavior. 

In stark contrast to the vast literature on the role of female pubertal timing in adolescence, the literature on long-term implications is remarkably limited. For this reason, the second main aim of this dissertation was to study the adult implications of female pubertal timing. For papers III and IV, we examined the long-term implications of pubertal timing, particularly as it relates to somatic development. The findings suggest that pubertal timing does have future implications for women’s body perception and morphology, with early-developing females having higher body mass in adulthood, but only under certain circumstances. The findings of this dissertation help further understanding of the soma et psyche implications of female pubertal timing. They indicate that pubertal timing has concurrent and future implications. It seems, however, that timing is not everything. The developmental significance of female pubertal timing appears to be very different under different contextual conditions. Thus, it is only when girls’ psychological and social contexts are considered that fruitful predictions can be made. As such, the findings have important implications for prevention, policy and practice.   



Eight hundred years before Christ, Hesiod, a Greek didactic poet, coined the phrase “Observe due measure, for right timing is in all things the most important factor”. Today, we would say “Timing is everything”. For many years, this expression has been widely used in as different contexts as car sales, cancer therapy, and everyday language. According to the existing research literature, it can be applied to the developmental significance of female puberty as well (Pinyerd & Zipf, 2005). 

Adolescence is a period of dramatic emotional, cognitive, social, and biological change (Patton & Viner, 2007). It takes place after what is one of the longest childhood periods of all mammals (Grumbach & Styne, 2003). Some of the most fundamental changes in adolescence are biological, and the biological changes associated with puberty are commonly regarded as a signal of the onset of adolescence (Petersen, 1998). Puberty refers to the biological changes that are needed for sexual maturity, which all healthy individuals experience. With this transition, girls go from having the appearance of children to resemble the appearance of the adult female stereotype (Tanner, 1978). The term puberty stems from pubertas, which means adult in Latin, or pubescere, which means growing hairy. The Merriam-Webster online dictionary (2007) defines puberty as “the condition of being or the period of becoming first capable of reproducing sexually marked by maturing of the genital organs, development of secondary sex characteristics, and in the human and in higher primates by the first occurrence of menstruation in the female”. Thus, the essence of female puberty is sexual maturation.