Older Fathers and Birth Defects

October 20th, 2006

Men are physically able to father a child much later than women can normally conceive.  But, the risks increase with the age of the father.

It has long been known that older women have a higher chance of giving birth to a baby with Down Syndrome.  This occurs in less than 1 in 1,000 women under 30, 1 in 400 at 35, and 1 in 6 by age 50.

Researchers now say that the same can be said for older fathers.  Compared to fathers between 20 and 29, the incidence of Down Syndrome increased by 15 percent in men over 35, 30 to 40 percent in men over 40, and 300 percent higher in men over 50.

Older Father Older men also have a higher risk of fathering children with Achondroplastic Dwarfism, Marfan Syndrome, or Myositis Ossificans.

New studies also show that older fathers are far more likely to have children with schizophrenia than men under 25.  This increase is 200 percent higher in men between 45 and 49, and 300 percent higher in men over 50.  The age of the mother appears to have no influence.

The risk of autism also increases with the father’s age but not with the mother’s age.  Autism is 5.75 times more likely among children born to men ages 40 to 49, compared with those born to men under 30.

In the old days, it was natural for men to marry before the age of 20, and women were even younger.  Both sexes are most fertile at around 24.  Taking into account the fact that most teenage pregnancies occur on the first “try,” it is probably more accurate to say that both are most fertile from puberty until the age of 24.  Physically, it does make sense to marry before or during the period of peak fertility instead of 5 to 15 years after.

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