Table 1 Sociodemographic characteristics of the study population

Mother's age, mean (SD)

29.1 (5.4)

29.0 (6.1)

30.6 (6.2)

Father's age, mean (SD)

32.0 (6.0)

NA

33.3 (7.0)

Mother's nationality (Spain), %

74.5

51.3**

46.6

Father's nationality (Spain), %

74.8

51.3**

44.6

Mother's working (yes), %

51.8

52.8

61.9

Father's working (yes), %

91.8

91.4

95.4

Mother's profession, %

6.9

10.8*

14.6†

Professional

17.5

12.4

12.5

Managerial and technical

37.6

35.8

41.6

Skilled (non-manual)

21.7

24.5

18.8

Skilled (manual)

16.4

16.5

12.5

Unskilled

Father's profession, %

6.2

8.9

16.7†

Professional

10.7

10.9

6.9

Managerial and technical

22.7

19.4

12.5

Skilled (non-manual)

57.8

56.6

58.3

Skilled (manual)

2.6

4.2

5.6

Unskilled