SEX CHROMATIN FREQUENCY IN BUCCAL MUCOSAL TISSUE - NORMAL FEMALE POPULATION

A method of recording sex chromatin scores with a reproducibility of ± 3% at two standard deviations is described. In 25 clinically normal women (control group) the frequency of sex chromatin was 40.8 ± 2.56%. The sex chromatin frequency in eight pregnant women did not differ significantly from that found in the control group (t31 = 1.54; P > 0.05). The sex chromatin frequency in 20 newborn females was significantly lower than that recorded for the control group (t40 = 10.97; P < 0.001). Regression analysis showed that increasing sex chromatin frequency over the first six days of life was strongly related to the effect of days. Reasons are given for attributing this finding to a difference in the buccal mucosal tissue between the newborns and adult females rather than to the effect of different hormonal levels. © 1969 S. Karger AG, Basel.