Studies on the ability to taste phenylthiocarbamide; red-green colour blindness and the age at menarche in Johannesburg Chinese school children.

The sample, although small, represents the total number of children attending the Johannesburg Chinese Kuo Ting Primary and High School in 1972 to 1974. The frequency of the non-taster gene was found to be 0,167 in the combined male and female sample. The gene for red-green colour blindness is present in the Johannesburg Chinese population but at low frequnecy, 0,012. The mean age at menarche was found to be 12,8+/-1,23 years and is younger than the mean ages recorded for a number of Caucasoid populations. It is suggested that this difference in mean age reflects possibly varying genetic rather than varying socio-economic factors.