Table 1.
Demographic characteristics of the Sibling Interaction and Behavior Study sample
| Adoptive families | Biologically related families | |
|---|---|---|
| Number of families | 246 | 130 |
| Older sibling | ||
| % Female | 61 | 52 |
| Age (years) | ||
| M | 16.1 | 16.3 |
| SD | 1.6 | 1.4 |
| Ethnicity | ||
| % Asian | 62.2 | 0 |
| % Caucasian | 29.7 | 93.8 |
| % Other | 8.1 | 6.2 |
| IQ | ||
| M | 106.6 | 107.1 |
| SD | 14.1 | 13.0 |
| Younger sibling | ||
| % Female | 61 | 52 |
| Age (years) | ||
| M | 13.8 | 14.1 |
| SD | 1.7 | 1.5 |
| Ethnicity | ||
| % Asian | 46.3 | 0 |
| % Caucasian | 43.9 | 93.8 |
| % Other | 9.8 | 6.2 |
| IQ | ||
| M | 107.0 | 107.7 |
| SD | 14.4 | 12.2 |
| Mother | ||
| % College degree | 58.5 | 46.9 |
| # Externalizing symptoms | ||
| M | 1.7 | 2.0 |
| SD | 4.2 | 3.1 |
| Father | ||
| % College degree | 61.4 | 44.6 |
| # Externalizing symptoms | ||
| M | 3.1 | 5.1 |
| SD | 3.3 | 7.2 |
Only same sex pairs were included in this study