study ties father's age to higher rates of psychiatric, academic problems in kids

http://www.eurekalert.org/pub_releases/2014-02/iu-ist022114.php

PUBLIC RELEASE DATE: 26-Feb-2014
Contact: Brian D'Onofrio
Indiana University

IU study ties father's age to higher rates of psychiatric, academic problems in kids

BLOOMINGTON, Ind. -- An Indiana University study in collaboration with medical researchers from Karolinska Institute in Stockholm has found that advancing paternal age at childbearing can lead to higher rates of psychiatric and academic problems in offspring than previously estimated.

Examining an immense data set -- everyone born in Sweden from 1973 until 2001 -- the researchers documented a compelling association between advancing paternal age at childbearing and numerous psychiatric disorders and educational problems in their children, including autism, ADHD, bipolar disorder, schizophrenia, suicide attempts and substance abuse problems. Academic problems included failing grades, low educational attainment and low IQ scores.

Among the findings: When compared to a child born to a 24-year-old father, a child born to a 45-year-old father is 3.5 times more likely to have autism, 13 times more likely to have ADHD, two times more likely to have a psychotic disorder, 25 times more likely to have bipolar disorder and 2.5 times more likely to have suicidal behavior or a substance abuse problem. For most of these problems, the likelihood of the disorder increased steadily with advancing paternal age, suggesting there is no particular paternal age at childbearing that suddenly becomes problematic.

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The working hypothesis for D'Onofrio and his colleagues who study this phenomenon is that unlike women, who are born with all their eggs, men continue to produce new sperm throughout their lives. Each time sperm replicate, there is a chance for a mutation in the DNA to occur. As men age, they are also exposed to numerous environmental toxins, which have been shown to cause mutations in the DNA found in sperm. Molecular genetic studies have, in fact, shown that sperm of older men have more genetic mutations.

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