Genealogical Structures and Consanguineous Marriage [and Comments and Replies]

It has been shown that mean age differences between genealogical relatives can take on a stable structure. It has further been discovered that in some populations the age differences among relatives preclude systematic sister exchange and bilateral first-and/or second-cross-cousin marriage. These discoveries have been generalized by some who argue that systematic sister exchange and bilateral cross-cousin marriage cannot occur in populations such as those in Australia, where husbands are substantially older than their wives. The classic interpretations of Kariera and Aranda systems are thus further undermined. The present paper shows this conclusion to be wrong; systematic sister exchange and bilateral cross-cousin marriage are possible in populations where birth-order-sensitive female infanticide or other extra female mortality results in systematic age differences between cross-sex siblings. It is also shown that the relative frequencies as well as the mean ages of the various types of genealogical rela...