Abstract

A significant fall of 33% has occurred in the incidence of twins in Greece over the past 45 years. In 1933-5 the twinning rate in the whole country was 14.3 per 1000; in 1974-6 it was 9.6 per 1000. The decline was smaller in Greater Athens than in rural and urban areas outside the city. Changes in the fertility behaviour of the women of Greece, a reduction in parity, and the shorter reproductive life of mothers, were the main reasons for the decline in the incidence of twins. The pattern of change has been different in the rural and urban populations outside Athens, which explains the steeper decline in the twinning rate in those areas.