Ireland is producing more boys than girls -- a birth trend some experts believe is due to fathers having a lot of sperm.

The Republic’s Central Statistics Office shows that male births have consistently outnumbered those of girls every year since 2000.

Last year 36,472 girls were born, but the boy boom continued with 38,593 males making their debut.

As life expectancy increases, however, the girls are more likely to outlive the boys and prove the more resilient sex.

A baby boy born in 2006 is expected to live 76.8 years, while for girls it is 86.6 years and more longevity is predicted in the coming decades.

Several theories were put forward for spikes in boy births.

Researchers said that the likelihood of giving birth to a boy or a girl was inherited.

Men are thought to be more likely to have sons if they have more brothers, but are more likely to have daughters if they have more sisters.