Male Biological Clock is Ticking, Too
Older Age Affects Male Fertility, Especially After Age 45
June 26, 2003 - It takes two to tango, and when it comes to
making a baby, the age of both dancers may play an equally important role. A
new study shows that the age of the male partner can have just as big an impact
on fertility and the time it takes to successfully conceive a child as the age
of the mother.
Researchers found it takes up to five times as long for a man
over 45 to get a woman pregnant than if he was under 25. Although the impact of
age on a woman's fertility has been well-studied, experts say this is the first
time such a strong association has been found between age and male fertility in
the time it takes to conceive a child.
"It's always been said that men make sperm every day, and
women are born with all eggs they're going to have, so the effect of male age
on fertility hasn't been perceived as a major issue until now," says
researcher Stephen Killick, MD, professor of reproductive medicine at the
University of Hull, U.K. "But in this particular case, there was just as
strong an association with male age and infertility, and, statistically, it was
even stronger than the woman's age."
Fertility Declines With Male Age
The study, published in the June issue of Fertility and
Sterility, compared the time to conception among a group of 2,112 pregnant
women. Each of the women filled out a questionnaire about the time it took to
achieve pregnancy, the age of both partners, and individual lifestyle
characteristics of both partners.
Overall, researchers found that age was the most significant
factor that affected the time it took to conceive, but there were small
relationships with other factors already known to increase the risk of female
and male infertility, such as caffeine or alcohol use and smoking.
Killick says the average time to conception for a woman with a
male partner under 20 was 4.5 months but that time rose to 26 months for a
50-year-old man. Compared to men who were under 25, men over 45 were nearly
five times as likely to have a time to pregnancy of more than one year and more
than 12 times as like to have a time to pregnancy of more than two years.
The study also showed that male age remained a strong
contributing factor to infertility even after accounting for other factors such
as frequency of intercourse and the age of the female partner.
Sexual Function Isn't Everything
Peter Schlegel, MD, acting chairman of the department of
urology at Weill Cornell Medical Center in New York City, says there have been
a lot of bits and pieces of information on male age and fertility, but
"this is the most definitive study to look at the issue and sort out the