Post-migration adaptation and age at menarche in the second generation of migrants.

Age at menarche is one of the most important measures of sexual maturation in girls. Since it has a high level of ecosensitivity, early environmental stress may trigger early puberty. One of these stress factors may be parental stress caused by the change of living conditions related to migration and adaptation to the new environment. Therefore, the aim of this study was to investigate the relationship between parental migration status and the timing of sexual maturity in second generation, i.e. migrants' daughters. Data were collected during the 2(nd) Polish Anthropological Survey carried out in 1966 - 1969. The information on age at menarche as well as demographic and social characteristics were collected by the use of a questionnaire. The results show that the age at menarche has been accelerated in girls from low socioeconomic status (low-SES) migrant families in comparison to low-SES non-migrant families. This study provides new biosocial evidence on the impact of the parental long-lasting post-migration adaptation on the timing of maturation in the second generation of migrants.