Few systematic data exist on survival and reproduction among males with
birth defects and their contribution to occurrence of birth defects in the
To estimate survival of males with registered birth defects, their subsequent
reproduction rates, and their risk of transmitting birth defects to their
Design and Setting
Population-based cohort study of data from the Medical Birth Registry
A total of 486 207 males born in Norway between 1967 and 1982,
12 292 of whom had a recorded birth defect.
Main Outcome Measures
Survival rates through 1992, reproduction rates through 1998, and risk
of birth defects among offspring of males with vs without birth defects.
Survival through 1992 was lower among males with birth defects (84%
vs 97%). Compared with males without birth defects, affected males were 28%
less likely to have had a child. Among offspring of affected males, 5.1% had
a registered birth defect compared with 2.1% of offspring of males without
birth defects (relative risk [RR], 2.4; 95% confidence interval [CI], 1.9-3.0).
Offspring of affected fathers had an increased risk of the same defect as
their fathers (RR, 6.5; 95% CI, 4.0-10.4) and an increased risk of dissimilar
defects (RR, 1.8; 95% CI, 1.3-2.5).
Compared with unaffected males, males with birth defects have higher
mortality and survivors are less likely to have a child. Fathers with birth
defects are significantly more likely than unaffected fathers to have an affected