Psychological Study of Sexual Maturity and Developmental Environment

青春期年龄有一个历史性的下降趋势，在大多数工业化国家被称为“长期趋势”。但是，很明显，在包括日本在内的一些地区，这一趋势似乎已经停止。20世纪80年代左右，日本首次出现了这种早熟趋势的停顿。本文介绍了对日本女学生月经初潮年龄的研究结果。这些材料是在2002年2月收集的。该研究随机抽样了64270名9-15岁的女学生。采用Probit分析法分析月经初潮的现状资料。2002年日本女学生月经初潮平均年龄为12岁零2.0个月（SD=1y）。和2.7米)。相比之下，1997年的平均年龄为12岁零2岁。Omonths。1997年至2002年的平均年龄相同，但1987年的平均年龄为12岁零5.9个月。可以看出，平均年龄下降了3。7个月。在日本，这显然是一种早熟的新趋势，因为在20世纪80年代，月经初潮早期出现的长期趋势在12岁零6个月左右停止了。目前，日本的平均月经初潮年龄被认为是第二次冻结，尽管早熟女孩的比例被认为在增加。青春期持续时间的个体差异被认为正在增加，这些差异可能与社会心理因素和健康习惯有关。

The age at puberty has a historical decline, known as "the secular trend" in most industrialized countries. But, it is apparent that the trend seems to have ceased in a number of locations, including Japan. Such a halt in the trend towards earlier maturation became apparent for the first time in Japan around the 1980s. This paper presents the results of a study of menarcheal age among Japanese schoolgirls. The material was collected in February 2002. It consisted of a random sampling of 64,270 schoolgirls (9-15 years old). Status quo data on menarche was analyzed by Probit analysis. The mean age at menarche of Japanese schoolgirls in 2002 was to be 12 years and 2.0 months (SD=1y. and 2.7m). In comparison, the mean age in 1997 was 12 years and 2. Omonths. The mean was the same between in 1997 and 2002, However, in 1987 the mean age was 12 years and 5.9 months. It can be seen that the mean age has decreased 3. 7months. This was obviously a new trend toward early maturation in Japan as the secular trend for the earlier appearance of menarche stopped in the 1980s at around 12 years and 6 months. At present the mean menarcheal age in Japan is thought to have frozen for the second time, although the percentage of early mature girls is thought to be increasing. Individual differences in the duration of puberty are thought to be increasing and these differences are possibly related to psychosocial factors and health habits.