This article presents a phylogenetic approach to studying sexual dimorphism of stature. Results show a significant association between sexual division of labor and sexual dimorphism of stature.

The ability of adults to digest lactose is common only in populations of European and circum-Mediterranean origin, a distribution thought to be a result of genetic adaptation to drinking milk from domestic livestock. Two additional hypotheses have been proposed to explain the distribution of high lactose digestion capacity: (1) supplemental calcium in high-latitude populations prone to vitamin D deficiency and (2) maintenance of water and electrolytes in the body in highly arid environments. However, these hypotheses are confounded by the shared ancestry of populations whose lactose digestion capability has been tested. Therefore, the authors test all three hypotheses using a phylogenetic comparative method for 62 cultures.

Through phylogenetic comparison, Holden and Mace explore the relationship between descent and cattle among a sample of 68 Bantu/Bantoid-speaking populations in Africa. The authors posit that when matrilineal cultures adopt cattle, they become patrilineal. Possible theories are offered to explain trends and variation in the data.

Can physiological variation in human populations be attributed to environmental variables? Arguing for the importance of phylogenetic comparative methods, the authors present the results of previous research by Holden & Mace (1997) on lactose intolerance as well as introduce new research on sex ratio at birth. The authors suggest that global variance in sex ratio at birth is an adapted response to the physiological costs of giving birth to boys in high fertility populations.