Scientists concluded that the 20s and early 30s are the ideal years for fatherhood

Older fathers have low-IQ babies Tue, 10 Mar 2009 18:23:36 GMT

Children fathered by older men are less intelligent and perform worse in brainpower and neurocognitive tests in their early years. Previous studies had linked advanced maternal age to reduced fertility rate, adding that increased paternal age is associated with certain health problems such as an increased risk of birth deformities and neuropsychiatric conditions (schizophrenia, autism and bipolar disorder). These studies had also reported that children born from older mothers score above average in intelligence tests. According to a study published in the PLoS Medicine, increased paternal age lowers the child's cognitive function in abilities such as memory, learning and concentration. These children, however, have a better access to health and educational services. The average score on the Stanford Binet Intelligence Scale is nearly 6 points lower in children born to fathers aged 50 compared to those born to fathers aged 20. Genetic mutation commonly seen in male sperm with aging is believed to be the factor contributing to this problem as well as the higher number of genetic defects in such children. Scientists concluded that the 20s and early 30s are the ideal years for fatherhood. PKH/HGH

Time is not on the side of older dads

Time is not on the side of older dads

March 10, 2009University of Queensland research has revealed the older a dad is the more likely his children will have reduced cognitive abilities.Professor John McGrath, from UQ's Queensland Brain Institute, said the study could have implications for a society that is having children later in life.

He said while recent research had shown a link between the age of a father and an increased chance of schizophrenia and autism in the children, there has been less focus on the age of father and cognition."The results were quite startling as it was thought that the age of the father was less of a concern compared to the age of the mother," Professor McGrath said."Now we are getting more evidence of the age of the father being just as important."The older a dad is, the worse his children tend to do in intelligence tests."The research, published in medical journal PLoS Medicine today (Tuesday, March 10), re-analysed data from one of the largest studies of children in the United States, the Collaborative Perinatal Project.More than 33,000 children were tested at eight months, four years and seven years on a variety of intelligence tests, and when Professor McGrath and his colleagues looked at the results against the age of the fathers a pattern soon became clear."Frankly, we were surprised to come up with such a clear cut finding," Professor McGrath said."We are concerned that older men accumulate more mutations in the developing sperm cells."These mistakes then pile up and increase the risks of problems in the children, and it is possible that these mistakes will carry on into the next generation."Professor McGrath said the difference in intelligence was the exact opposite for children of older women, which made the findings even more startling."Offspring of older women do better in similar tests, but this is usually put down to socio-economic status of women," he said."But with the older dads, we wonder if the association is related to mutations in the developing sperm."Professor McGrath and colleagues at QBI and the Queensland Institute of Medical Research are currently using mouse models in order to find the underlying genetic factors that may explain the association between advance paternal age and child development. Research Australia

Also non-familial autism, schizophrenia cancers results

Kids with older fathers ‘are less intelligent’
Submitted by Mohit Joshi on Sun, 03/08/2009 - 08:14.
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London, Mar 8 Are you delaying fatherhood? Well, then you should reconsider your family plan, for a new study has found that kids with older dads perform badly in intelligence tests.
The research, led by John McGrath, of the Queensland Brain Institute at the University of Queensland in Australia, found children with older fathers tended to obtain significantly lower scores in a variety of cognitive tests than those born to younger fathers.
"The offspring of older fathers show subtle impairments on tests of neurocognitive ability during infancy and childhood," The Times quoted John, as saying.
"In light of the trends to delay fatherhood, the clinical implications and the mechanisms underlying these findings warrant closer scrutiny," he added.
To reach the conclusion, McGrath analysed data on 33,437 Americans born between 1959 and 1965. All were tested at eight months, four years and seven. The data set, despite its age, remains one of the best resources.
The underlying biological mechanisms are the key questions, according to McGrath. One idea is that as men age the cells that produce sperm suffer increasing numbers of mutations, which are passed on to an offspring. (ANI)

James Watson co-discoverer of DNA structure makes the connection between older paternal age and his son's schizophrenia

Sunday Times
March 8, 2009
Not too bright? Now the blame is on your old man
Jonathan Leake, Science Editor

CHILDREN with older fathers seem to perform worse in intelligence tests, according to a study due out this week.
They tended to obtain significantly lower scores in a variety of cognitive tests than those born to younger fathers, researchers have found.
The results could be controversial. Until recent years it had been thought that it was a mother’s age that had most impact on the health and abilities of children. The father’s age, by contrast, was thought to be much less important.
The research, led by John McGrath, of the Queensland Brain Institute at the University of Queensland in Australia, suggests such ideas need rethinking.
“The offspring of older fathers show subtle impairments on tests of neurocognitive ability during infancy and childhood,” he said. “In light of the trends to delay fatherhood, the clinical implications and the mechanisms underlying these findings warrant closer scrutiny.”
Other research has shown linkage between advanced paternal age (men over 35) and an increased risk of neurodevelopmental disorders, such as autism and schizophrenia, as well as dyslexia. Such findings prompted James Watson, co-discoverer of the structure of DNA, to speak of his concern. His son Rufus suffers from schizophrenia and as more is uncovered about its causes Watson has publicly questioned if he is to blame. “I worry that I was 42 with Rufus,” he says. “I read that the frequency of schizophrenia goes up with the age of both parents.”
The tests, designed to measure the ability to think and reason, also generated a second startling finding — that children with older mothers gain higher intelligence scores.
McGrath analysed data on 33,437 Americans born between 1959 and 1965. All were tested at eight months, four years and seven. The data set, despite its age, remains one of the best resources. McGrath also used advanced statistical techniques to remove environmental influences.
For McGrath one of the key questions is the underlying biological mechanisms. One idea is that as men age the cells that produce sperm suffer increasing numbers of mutations, which are passed on to an offspring.
Why, though, would children born to older mothers tend to have higher intelligence? McGrath suggests this is because women’s eggs are formed when they are still in the womb and so their DNA is protected from mutation until they are used.