Table 1.
Family characteristics.
| Family characteristics | Values |
|---|---|
| Number of families | N = 56 |
| Number of children | N = 104 |
| Twin ages (months) | M = 8.6, SD = 3.6 months, Range = [3.4, 16.9] |
| Twin couplet Zygosity | Monozygotic (MZ) N = 27 (51.8%) Dizygotic (DZ) N = 21 (41.1%) Unknown N = 4 (7.1%) |
| Twin gender assigned at birth | Both Boys N = 18 (32.1%) Both Girls N = 28 (50.0%) One Boy, One Girl N = 10 (17.9%) |
| Twin gestational age (weeks) | M = 36.8, SD = 1.5 weeks |
| Respondent | Mother N = 50 (89.3%) Father N = 1 (1.8%) Unknown N = 5 (8.9%) |
| Mother's age (years) | M = 32.1, SD = 4.9 years, Range = [22.3, 47.8] |
| Father's age (years) | M = 34.6, SD = 7.2 years, Range = [24.4, 67.2] |
| Family income1 | M = 5.71, SD = 2.28 years, Range = [1, 10] |
| Parent education2 | M = 3.31, SD = 1.14, Range = [1, 10] |
1Family income per month. Scale 1 to 10 where 1 = <20K, 2 = 20-30K, 3 = 30-40K, 4 = 40-50K, 5 = 50-60K, 6 = 60-70K, 7 = 70-80K, 8 = 80-90K, 9 = 90-100K, and 10 = >100K (SEK). 1.0 SEK = 0.105 $ (USD), 100K SEK/Month = $126K USD/Year at the time of the study. 2Education level on a scale from 1 to 4, where 1 = Primary, 2 = Secondary, 3 = Undergraduate ( ≤ 3 years) and 4 = Postgraduate level (>3 years).