title: Brief report: parental age and the sex ratio in autism.
abstract: The male-to-female (M:F) ratio for autism spectrum disorders (ASD), typically about 4:1, appears to decrease with increasing paternal age, but this relationship has not been systematically tested. With 393 ASD cases from families with two or more ASD cases, we categorized paternal age into five age groups (<30, 30-34, 35-39, 40-44, 45+) and found that the M:F ratio was significantly decreased with increasing paternal age groups and remained so after also adjusting for maternal age. No significant relationship between maternal age group and the M:F ratio was observed. This study suggests that the M:F ratio is reduced with increasing paternal age consistent with de novo genetic or genomic anomalies arising more frequently as men age and then conceive children.
authors.affiliation: Harvard University, Cambridge, MA, USA.
authors.forename: Alene
authors.initials: A
authors.lastname: Anello
authors.forename: Abraham
authors.initials: A
authors.lastname: Reichenberg
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Luo
authors.forename: James
authors.initials: J
authors.lastname: Schmeidler
authors.forename: Eric
authors.initials: E
authors.lastname: Hollander
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Smith
authors.forename: Connor M
authors.initials: CM
authors.lastname: Puleo
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Kryzak
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Silverman
mesh_terms: D000328:Adult; D000367:Age Factors; D001321:Autistic Disorder / Q000235:genetics*; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D010290:Parents; D010331:Paternal Age; D012744:Sex Ratio; D055815:Young Adult