In all recorded populations, women are on average shorter than men; in a
survey of European, Asian, African and American populations reported by Stini
(1975: 125), for example, the range in the ratio of male to female adult mean
stature was 1.046 to 1.090. A number of human biologists and physical
anthropologists have attempted to explain this inter-population sexual dimorphism
in stature: cultural and environmental inf luences do not appear to explain
much of the variation in sex differences, and it is suggested that the interpopulation
variation in sex difference has a strong genetic component (Eveleth,
1975; Gray and Wolfe, 1980). Inter-population variation in sex differences in
mean stature by social class, and changes in the ratio of male to female adult
mean stature for the same population over time, however, are attributed to
environmental influences. lt is suggested that, because of the female's greater
investment in reproduction to supporl pregnancy and lactation, girls are more
protected than boys againsthe effects of malnutrition and disease during the
period of growth. Being more influenced by the effects of the environment,
males show greateresponse to the removal of environmental stress. lt follows
that the ratio of male to female mean height should be higher for the better off
social classes who are more nutritionally secure and less exposed to disease.
Similarly, as nutrition improves and morbidity is reduced over time, the ratio of
male to female mean height should increase pari passu with the increase in the
mean height of the population (Eveleth and Tanner, 1990: 200; Bielicki, 1986,
Vol. 3: 298; Stinson, 1985: 123; Tobias, 1972:98-101). The ratio of male
to female mean height becomes, in effect, an indicator of environmental
betterment,hough Tobias (1972. 101) is careful to add a caveat: it does not
necessarily follow that in populations which are well nourished and suffer
relatively low levels of morbidity, further betterment in environmental conditions
will have the same effect on sexual dimorphism in stature as in extremely
def icient populations. And Kuh, Power and Rogers (1991) documenthat
in 20th century western countries this relationship between environmental
improvement and changes in the sexual dimorphism in stature is not well
def ined