Trends in the male proportion of live births in Ireland were examined by extracting the numbers of male and female live births from Registrar General's Reports (1864-1952) and Department of Health Annual Reviews (1953-1996), and subjecting them to statistical analysis. Except for 10 years (1947-1956) the proportion of male births has risen, significantly so since 1957. The global fall in male proportion of live births in recent decades has not been seen in Ireland, even though the country has undergone progressive industrialisation. It would be prudent not to assume that the same environmental factors alter sex ratio and cause pathological changes in male reproductive organs.