Distribution of Exchanges on Chromosome 21q Stratified by Parental Origin and Age
| Female meioses | Male meioses | |||||
| No. of exchanges | age (yr) | age (yr) | ||||
| <25 | 25–35 | >35 | <25 | 25–35 | >35 | |
| 0 | 22 | 40 | 7 | 16 | 43 | 15 |
| 1 | 18 | 42 | 9 | 14 | 42 | 16 |
| 2+ | 9 | 8 | 4 | 1 | 2 | 1 |
| Total | 49 | 90 | 20 | 31 | 87 | 32 |
| χ2, 4 d.f. | 4.1 | 0.3 | ||||
| p-value | 0.40 | 0.99 | ||||
[i] The observations in Table 2 were reclassified by parental age (yr) and contingency analysis used to test for age-related trends.