Age and Sex Correlations on the Cross Section of Parietal Hair

Abstract

Cross sections of parietal hair of 1024 males and 2046 females of various ages were measured. The maximum and minimum diameters of the hair shaft and the hair index were statistically studied in terms of age and sex.
The maximum and minimum diameters in the cross section of the hair shaft were very variable depending upon age.
In males, both diameters change with a rather linear relationship to age, while in females they show a rather smooth curve relationship. In infancy and childhood, the diameters in males are larger than those in females, but in adults, they are smaller in males than in females.
In females, a diameter to age correlationship shows two phases at 13 and 48 years of age respectively.
Except infancy, in both sexes, the hair index in the cross section of the hair shaft is almost constant irrespective of age.
It seems that studies of parietal hair on the cross section shoud not be made without a careful consideration of age and sex.