The young and the elderly: The birth rate in the State will increase significantly over the next 15 years, while the number of people aged 65 or over will rise even faster, the Central Statistics Office (CSO) report forecasts.
The figures project that by 2021 the number of births will have risen to 63,000 per year compared to 58,000 in 2001.
However, increases in the birth rate will only occur in four regions, with the most significant increase forecast for the west where it is projected that there will be 2,000 additional babies born annually.
The report suggests that in 2021 Dublin and the mid-east region (Meath, Wicklow and Kildare) will account for 41 per cent of all births - the same as at present.
The figures forecast that the young population - those in the 0-14 age group - will increase in all regions in the period up to 2021, with the most pronounced rises in the mid-east (43 per cent), the west (36 per cent) and in Dublin (26 per cent).
"The results in all regions are affected by the projected increases in the numbers of women of child-bearing age which will more than compensate for the assumed declines in fertility rates of these women."
The CSO forecasts that there will be an increase of around 20 per cent in the number of people aged 15-24 in the mid-east region. There will be an increase of 4 per cent for this age category in the midlands. All other regions will experience decreases in this group.
"Major increases are projected in all regions between 2002 and 2021 for those aged 24 to 64, reflecting earlier birth cohorts joining the population of working age.
"Projected gains from external migration will also exert a strong influence on this age group. Of particular note is the projected almost doubling of the number of persons aged 45-64 in the mid-east region."
The forecast suggests that the number of older people - those 65 or over - will increase in every region by 2021. It projects there will be a 133 per cent rise in the numbers in this age group in the mid-east and a 75 per cent growth in Dublin.
The population aged 80 and over is projected to rise by two-thirds by 2021, with increases of 90 per cent projected for Dublin and the mid-east.
