Table 1. Sample Sizes by Twin Registry and Age Group (Total N = 2,618 twins from 1,100 complete and 209 incomplete pairs).
| MSUTR | MTFS | ATR | Total | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Age Group | Total | MZ | DZ | Total | MZ | DZ | Total | MZ | DZ | Total | MZ | DZ |
| 10-12 yrs | 172 | 84 | 88 | 0 | 0 | 0 | 0 | 0 | 0 | 172 | 84 | 88 |
| 13-15 yrs | 146 | 78 | 68 | 532 | 342 | 190 | 0 | 0 | 0 | 678 | 420 | 258 |
| 16-19 yrs | 152 | 94 | 58 | 24 | 26 | 22 | 0 | 0 | 0 | 200 | 120 | 80 |
| 20-25 yrs | 164 | 92 | 72 | 516 | 346 | 170 | 0 | 0 | 0 | 680 | 438 | 242 |
| 26-30 yrs | 16 | 8 | 8 | 0 | 0 | 0 | 334 | 206 | 128 | 350 | 214 | 136 |
| 31-41 yrs | 0 | 0 | 0 | 0 | 0 | 0 | 538 | 348 | 190 | 538 | 348 | 190 |
| Total | 650 | 356 | 294 | 1,072 | 714 | 382 | 872 | 554 | 318 | 2,618 | 1,624 | 994 |
Note. MSUTR = Michigan State University Twin Registry; MTFS = Minnesota Twin Family Study; ATR = Australian Twin Registry; MZ = monozygotic; DZ = dizygotic. Values are the number of twins per age category and twin registry.