Table 1. Characteristics of the Study Participants in the Parental Age Cohort in Denmark.
| Characteristic | Parental age cohort (N = 1 476 783)a |
|---|---|
| Sex of children | |
| Male | 758 066 (51.3) |
| Female | 718 593 (48.7) |
| Missing | 124 (0.01) |
| Birth year of children | |
| 1990-1994 | 311 116 (21.1) |
| 1995-1999 | 322 993 (21.9) |
| 2000-2004 | 310 903 (21.0) |
| 2005-2009 | 306 592 (20.7) |
| 2010-2013 | 225 179 (15.3) |
| Parity of the mother | |
| 1 | 647 801 (43.9) |
| 2 | 550 614 (37.3) |
| ≥3 | 278 368 (18.8) |
| Maternal education | |
| Primary and low secondary | 315 194 (21.3) |
| Upper secondary and academy profession degree | 684 001 (46.3) |
| Bachelor’s degree or higher | 451 682 (30.6) |
| Missing | 25 906 (1.8) |
| Maternal country of origin | |
| Country other than Denmark | 188 930 (12.8) |
| Denmark | 1 286 903 (87.1) |
| Missing | 950 (0.1) |
a
Singleton births in 1990 to 2013 with complete information on parental age in Demark.