An analysis of paternal age and 47,+21 in 35,000 new prenatal cytogenetic diagnosis data from the New York State Chromosome Registry: no significant effect.

In 35,680 fetuses of women who had prenatal cytogenetic diagnosis done upon amniotic fluid specimens obtained during 2nd trimester amniocentesis and in whom there was no increased cytogenetic risk except for age, there was no statistically significant evidence for an increase of 47,+21 at any paternal age after adjustment for maternal age. The ratio of observed-to-expected numbers in fathers less than 30 years old was 1.0 and in fathers 40 years or older was 0.9 when compared with numbers derived from maternal-age-specific rates in men 30-39 years old. The ratio was 1.1 for those younger than 34 years when compared with rates in fathers aged 34-39 years old. Only for men 55 years or older was there any, even suggestive, increase. The ratio was roughly 1.5 (9 observed to about 6 expected). This was not statistically significant, and moreover, the increase such as it was, was in men married to women 37-42 years old. Regression analyses using several additive parental age models introducing a parabolic function for paternal age, failed to reveal any paternal age contribution.