Abstract: The authors have mode inquiry about the menarchal age of more than 700 girls attending medical schools in Beijing as well as some informations about the occupation and records of formal schooling (RFS) of their parents. Several statistical methods were used to deal with the data obtained.
The results of deviation analysis points out that the parents occupations and RFS have very significant effects on their daughters menarchal age. In view of occupation, the girls with parents as teacher or researcher have the lowest menarchal age, the peasants' daughter have the highest, the workers' and officials' are in between. In view of KFS, the result is much clearer. The girls with university graduated parents have the earliest menarche followed by the girls with high school graduated parents, then those with junior middle school and the primary school. The girls in uneducated family are the latest. lf one noted that there were little relationships between the education level and the income, one would admit that the most important factor effecting Beijing girls' menarchal age is the cultural background of family instead of material condition.
From the sample of this paper, authors did not find significant effect of parent's native place on daughter's menarchal age.
Relationship analysis suggests that there is trend towards earlier menarchal age.
Because of the selected sample (there are much more individuals from well-educated family than it should be in ratio), the mean menarchal age of this paper is a little lower than that of nowadays population of Beijing girls.

Key words: Menarchal age