MONDAY, March 11, 2002 (HealthDayNews) -- Women know the longer they put off pregnancy, the riskier it can be for their baby's health.
Now, it seems, men who delay fatherhood are also genetically susceptible to the march of time.
A new study from Spain, which appears in the European Journal of Human Genetics, found that with every decade that passes, a man's risk of having sperm with chromosomal abnormalities increases 17 percent.
Chromosomes are the threadlike "packages" of genes and other DNA in the nucleus of a cell. Every human being has 46 chromosomes, one set of 23 from each parent.
However, chromosomal abnormalities can cause birth defects. For example, Down syndrome occurs when there are three copies of chromosome 21, rather than the normal two.
For this study, researchers from the University Autonoma of Barcelona, Spain, examined almost 200,000 sperm from 18 different men. The men were between the ages of 24 and 74, with an average age of 48.
The researchers used a test known as fluorescence in situ hybridization (FISH) to identify chromosomal abnormalities. The test lets scientists see chromosomes 6, 21, X and Y by attaching a fluorescent molecule to those chromosomes, which can then be viewed with a special light.
"The percentage of sperm [with double copies of each of these chromosomes] increases by 17 percent for every 10-year interval," says lead researcher Dr. Josep Egozcue, a professor of biology at the University Autonoma. "Sperm with two chromosomes 21 increases by 11.4 percent, and sperm with two sex chromosomes by 8.6 percent."
He suggests men over 55 who want to father a child should consider having their sperm analyzed for chromosomal abnormalities, but acknowledges that while the test is simple to perform, it's expensive.
Not everyone agrees testing is the best way to go.
"One sperm sample doesn't give you any guarantee," says Dr. Boris Petrikovsky, chairman of the department of obstetrics and gynecology at Nassau University Medical Center in East Meadow, N.Y. "You can do three sperm analyses 24 hours apart, and get three different results."
Petrikovsky recommends handling a pregnancy that involves an older father in much the same way physicians manage pregnancies with older mothers. That generally means more testing, like ultrasound and genetic tests, to assess the baby's health.
While it's important for older men and their partners to know that the men are more likely to have sperm with chromosomal abnormalities, Petrikovsky says the risk of birth defects is still very low.
What To Do: This article from the Fetal Alcohol Syndrome Alaska Project details how a man's behavior can affect the health of his baby. For more information on birth defects and their causes, visit the March of Dimes.
