This biocultural study examines patterns of infertility, or failure to produce live births, by female age cohorts in the Micronesian population of Butaritari Atoll, Kiribati. Anthropological and demographic methods employed included analysis of census survey, reproductive history collection, structured and semi-structured interviews, participant observation, ethnohistorical research, vital registrations, and clinic records. Primary infertility levels are found to be extremely low in this population. This is argued to be a consequence of low risk of exposure to fertility-inhibiting disease, typically extended exposures to coital activity, and a culturally-influenced resistance to birth-limiting behavior before at least one child is born. There is little reduction in fertility, and therefore in biological capacity for conception, before women reach the end of their thirties. This pattern of high fertility is maintained because of socio-culturally defined patterns of sexual behavior within marriage which tend to maintain coital activity despite increasing marriage durations, and therefore with increasing age. In the study's conclusion infertility patterns by age for this population are discussed in relation to issues of the role of physiological aging and infertility increases in human populations. It is concluded that studies of infertility by age need to be considered as culturally-grounded and population-specific, particularly in reference to patterns observed at the population level in female age groups under forty.

This thesis examines relationships between the social and physical environments of a village on Butaritari atoll in Kiribati. The system of ambilineal descent and land inheritance obtaining there results in complex networks of genealogical relationships which affect most aspects of social life, including land rights. While previous studies conducted in Kiribati have recognised the intimate connection between genealogy and land rights, none has investigated its ramifications for the distribution of land rights within a community. In contrast, this study engages that question as a central concern using a framework which integrates Bourdieu's concepts of social space, field and habitus with post-neo-Darwinian ideas about the relationship between organism and environment. The social space was found to be primarily structured by relationships based upon genealogy and secondarily by age and gender, each of which constituted a field within the wider social space. The genealogical field was defined by a network of positions, each representing a particular descent group. In accordance with the prevailing system of ambilineal descent, residents could belong to more than one descent group and it was upon the resulting networks of relationships between descent groups that the disposition of those groups within the genealogical field was defined. Because land-use rights were associated with genealogical connections the reconstruction of the genealogical field encompassing all of the village residents was a necessary precursor to discovering the distribution of those rights and the genealogical field was a central point of articulation between the social and physical spaces. The fields of age and gender relations provided further points of articulation between the social and physical spaces, the natures of which are examined through discussion of the material culture of the village and village and island politics. Despite a contemporary ideology of egalitarianism there were vestiges of a former hierarchy of social status groups. While the inter-group obligations, rights and responsibilities associated with this hierarchy were no longer practised, the association of contemporary residents with those social status groups bore a relationship to their position within the genealogical field and the amounts of land to which they shared rights.