Men May Have Biological Clocks, Too
Some researchers say a man's age may affect not only his ability to father a child -- but the health of his offspring.
Aging Dads: What Goes Wrong
Like every system in the body, experts say the male reproductive organs have
not been spared the ravages of time.
"First there seems to be some clear changes that happen on a purely
chemical level as a man ages. He has lower testosterone levels, lower DHEA,
lower estrogen, plus higher levels of FSH and LH, which signal pretty much the
same thing in men as in women -- reproductive failure," says Hackensack
University embryologist Dave McCulloh, PhD, director of laboratory services at
University Reproductive Associates in Hasbrouck Heights, N.J.
In a French study of nearly 2,000 men published in 2005 in the journal
Fertility and Sterility, doctors concluded that even in couples
undergoing IVF an aging father could figure into the pattern of pregnancy failure, more than previously
But it's not just the idea of making fewer babies that is of concern. The
new research is also tampering with conventional fertility wisdom, which has
long asserted that because new sperm is made daily, male fertility remains
And while the notion of unending sperm production hasn't changed, some
researchers now believe that as a man ages, the task of churning out that daily
supply is a little like trying to make a fresh batch of macaroni in a worn-out
In short, while the ingredients may be fresh, the mechanism that puts it all
together gets slower and works less efficiently with age. And that means far
fewer perfect macaroni -- and sperm -- to show for it.
Effects of Aging
"There is definitely evidence of weaknesses in the DNA of sperm as a man
ages. And this could be the result of a weakness anywhere in the sperm-making
system, from the copying mechanisms necessary to turn out new sperm every day,
to the natural ability of the body to correct mistakes in that copying process,
or really, any step along the way; any or all could become defective as a man
ages," says Kleinhaus.
While female fertility may be limited because women are born with a limited
number of eggs, Kleinhaus says it's boosted by the fact that the DNA-copying
process is complete at birth -- and not generally subject to mistakes along the
Conversely, while men may still be able to manufacture that daily supply of
sperm -- regardless of age -- Kleinhaus says they remain vulnerable to
bloopers, errors, and DNA foul-ups with each and every copy that's made.
"This just doesn't impact the rate of conception, we believe it can
impact the health of the baby or even the health of the pregnancy itself,"
Lifestyle: Another Break in the Sperm Chain
While the aging sperm machine may be one theory, McCulloh says there is an
equally strong possibility that it may not be the aging process at all that's
at fault, but rather what a man does over his lifetime that matters most.