Stress causes girls?

A study suggests that stress at conception can make your baby more likely to be female.

Published August 31, 1999 4:00PM (EDT)

If you're planning to have a baby soon and you're hoping for a boy, try to
keep your life stress-free. Research published in last week's
British Medical Journal suggests that enduring traumatic events around the time of conception can cut your odds of having a male baby.

Dr. Dorthe Hansen of the Danish Epidemiology Science Centre and colleagues
in Denmark analyzed the boy-to-girl ratio of 3,072 babies who were conceived around the time of a traumatic event in the mother's life. For the purpose of the study, a traumatic event was defined as the death of the mother's partner or an older child, or a serious illness in the family. The birth ratio of traumatized mothers was compared to a control group of mothers who were not exposed to traumatic events.

The research showed that only 49 percent of the traumatized mothers
gave birth to boys, as opposed to 51.2 percent in the control group. "The
results," the authors write, "show that severe life events may reduce the
sex ratio, especially for exposures around the time of conception."

But can a baby's sex really be traced to the mother's mental state? "It
sounds very far-fetched," says Dr. Bruce Shephard, an obstetrician in Tampa,
Fla., and co-author of "The Complete Guide to Women's Health" (Penguin
Press, 1997). He adds, "I've seen no such correlation."

Even the researchers admit that the study has limitations. The time frame
for observing the mothers was the year of childbirth and the previous year,
but in some cases the traumatic event -- a family illness, for example --
might have begun earlier. And other unmeasured stresses could have affected the mother's state of mind as well.

Still, the researchers stand behind their findings. Their report concludes
that "psychological stress related to severe life events may alter the sex
ratio through changes in sexual activity, changes in hormones around the
time of conception, reduced semen quality, or an increased rate of early
male abortion."

"Sounds like a theory," Shephard says. "Sounds like fluff. Psychological
trauma doesn't do anything."

Or does it? A recent
British study showed that anxiety during pregnancy can sometimes be dangerous for the baby-to-be. The expectant mother's psychological stress can restrict blood flow through the arteries that feed the uterus, which in turn can lead to a low birth weight.

And a
1996 study published in the Journal of Epidemiology showed that job-related stress can complicate pregnancy by causing high blood pressure. The authors wrote, "We would recommend that pregnant women who are working try to decrease the number of tasks they have to do in a day, decrease the length of the workday and generally ease the pressure a little bit."

Meanwhile, for those mothers-to-be who are crossing their fingers for baby
boys, psychological stress isn't the only issue. Previous research has shown
that a mother's exposure to physical duress -- earthquakes, floods -- can also lower the ratio of male births. One
study showed a "significant decline" in the boy-girl sex ratio following the 1995 Kobe, Japan, earthquake.

So, if you want a bouncing baby boy, perhaps it's best to steer clear of the fault lines.

By Jon Bowen

Jon Bowen is a frequent contributor to Salon.


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