Births to unmarried parents came to 4,312 in 2004, a figure which represented 22% of total births and was higher than in 2003 (19.9%), according to EUSTAT data. Alava and Bizkaia had higher percentages than the whole of the A.C. of the Basque Country, with 23.1% and 22.6%, respectively; Gipuzkoa was the only province with relatively low values (20.6%). Over the last 10 years the proportion of births to unmarried parents has doubled, as in 1995 it was 10%.

In 2004 the number of births in the A.C. of the Basque Country reached a figure of 19,594, which represented a 1.7% increase with regard to 2003; this increase was lower than between 2002 and 2003, when it came to 6.3%. The highest increase was in Álava, in 2004 (4.3%), followed by Bizkaia (1.9%) and Gipuzkoa (0.3%).

The birth rate stood at 9.3 per thousand inhabitants, far from the 20 per thousand that was registered in the 60s. The highest figure was found in Gipuzkoa (10‰), followed by Álava (9.6‰) and then Bizkaia (8.8‰).

The sharp fall in births started in 1976 and slowed down at the end of the 80s, reaching its lowest point in 1994. The figures for 2004 maintain the upward trend in births that started in 1995.

Three out of every four women who gave birth in 2004 were aged thirty or older. The largest group corresponded to women between 30 and 34 years of age, with 45.5% of total births. Furthermore, there was a rise in the group of mothers aged over 35 with regard to 2003 (30.2%), who continued to be much larger than the group of 25 to 29 year olds (18.8%). The average age of mothers was 32.2 years, while among first time mothers it was 31 years, similar figures to those for 2003.

Over the last decade, all the age groups of mothers under 30 years of age lost weight, the group of 25 to 29 year olds being the one who lost most (10 percentage points). By contrast, there was an increase of almost double among the age group of mothers aged 35 or over.

Taking into consideration the order of birth, first born represented over 57.7% in 2004, a similar proportion to the year before. By contrast, third and subsequent born children, who only constituted 6.3%, increased by half a percentage point with regard to 2003.

The number of births came to 19,269, 18,871 were single, 385 double, 12 triple and 1 quadruple.

The ratio of sexes among births in 2004 was 106 males for every 100 females. On average, boys weighed 3,300 grams and girls 3,180 grams.