Effects of parental reproductive behavior on offspring sex ratio in a pre-industrial western Mediterranean population (La Alpujarra, 1900-1950, SE Spain).

The reproductive behavior of parents of La Alpujarra (Spain) favorable to male offspring during the first half of the 20th century has been studied is this paper. The family size increased as daughters accumulated because mothers had more pregnancies in order to have higher male offspring, and the reproductive rhythm increased (birth interval decreased) when the first deliveries were only daughters. Although male mortality was higher than female in children older than one year, this reproductive behavior did not determine sex reversal of mortality in babies of between one month and one year, contrary to other developing populations.