Table 1 Demographic characteristics of participating and non-participating families
Participating families (n = 225) | Non-participating, eligible families (n = 131) | ||
|---|---|---|---|
Twin characteristics | |||
Age at recruitment M (SD) | 3.60 (0.58) | 3.56 (0.53) | p = .45 |
Gender (% boys) | 49.8 | 55.0 | p = .35 |
Country of birth (% Netherlands) | 99.6 | 100.0 | p = .45 |
Family characteristics | |||
Primary parent (%)1 | p = .97 | ||
Biological mother | 92.0 | 86.4 | |
Biological father | 8.0 | 7.6 | |
Age primary parent M (SD) | 36.81 (4.58) | 37.29 (4.51) | p = .39 |
Age second parent M (SD) | 38.45 (5.65) | 39.52 (4.78) | p = .11 |
Country of birth (% Netherlands) | |||
Primary parent | 95.1 | 92.8 | p = .39 |
Second parent | 96.0 | 92.8 | p = .21 |
SES – based on parents educational level (%) | p = .18 | ||
Low | 7.1 | 6.1 | |
Medium | 39.6 | 49.6 | |
High | 53.3 | 44.3 | |
Number of children in the family M (SD) | 2.82 (0.78) | 2.90 (1.00) | p = .41 |
Primary parents’ marital status (%) | p = .25 | ||
Married or registered partnership | 69.2 | 78.6 | |
Cohabiting | 26.8 | 16.8 | |
Single parent | 3.6 | 4.6 | |
Family type (%) | p = .28 | ||
Biological parent(s) | 98.2 | 96.1 | |
Adoptive parent | 0.9 | 0.8 | |
Step parent | 0.9 | 1.6 | |
Other | 0.0 | 1.6 | |