Table II.

Ajusted effect of parental age on agenesis (ACC) and hypoplasia of the corpus callosum (HCC) diagnosed < 1 year of age from a population of over 3 million live births in California from 1983 to 2003.

			ACC N = 472			HCC N = 158
	Births N = 3,440,576	N	Crude RR (95% CI)	Adjusted RR (95% CI)	N	Crude RR (95% CI)	Adjusted RR (95% CI)
Maternal Age adjusted for paternal age
< 20	414,783	53	0.88 (0.65−1.21)	0.72 (0.46−1.13)	15	1.03 (0.56−1.89)	1.14 (0.48−2.70)
20−24	865,000	99	0.79 (0.61−1.03)	0.74 (0.55−1.01)	38	1.25 (0.78−1.99)	1.42 (0.84−2.39)
25−29 (ref)	969439	140	---	---	34	---	---
30−34	761,934	103	0.94 (0.73−1.21)	0.91 (0.69−1.21)	35	1.31 (0.82−2.10)	1.23 (0.74−2.06)
35−39	351,811	48	0.94 (0.68−1.31)	0.83 (0.56−1.23)	23	1.86 (1.10−3.16)	1.35 (0.70−2.61)
40−55	76,637	21	1.90 (1.20−3.00)	1.67 (0.96−2.91)	12	4.46 (2.31−8.62)	2.79 (1.23−6.37)
Paternal Age adjusted for maternal age
< 20	151,991	17	0.96 (0.58−1.61)	1.20 (0.65−2.22)	5	0.79 (0.31−2.01)	0.79 (0.26−2.38)
20−24	612,014	84	1.18 (0.89−1.58)	1.36 (0.99−1.89)	21	0.82 (0.48−1.41)	0.75 (0.42−1.35)
25−29 (ref)	862,464	100	---	---	36	---	---
30−34	807,134	105	1.12 (0.85−1.48)	1.08 (0.80−1.44)	33	0.98 (0.61−1.57)	0.97 (0.58−1.62)
35−39	478,201	66	1.19 (0.87−1.62)	1.15 (0.81−1.64)	25	1.25 (0.75−2.09)	1.14 (0.62−2.09)
40−55	269,763	42	1.34 (0.94−1.93)	1.22 (0.79−1.88)	23	2.04 (1.21−3.45)	1.63 (0.82−3.26)