Analysis of birth intervals in a non-contracepting Indian population: an evolutionary ecological approach.

Reproductive strategies are related to ecological constraints. This paper examines data on early birth spacing in a scheduled caste, Bengali-speaking, non-contracepting population of the Karimganj district of southern Assam, India, taking an evolutionary ecological perspective. It is found that on average birth intervals closed by boy-boy are longer than those closed by girl-girl. Birth spacing tends to be longer among upper-income and Craftsman sub-caste mothers. The presence of a 'grandmother' in the household shortens spacing. These findings are compatible with an evolutionary-based reproductive decision-making process.