| Born to Be a Tomboy?
-- Why do some girls love to wear dresses and play tea party while
others prefer climbing trees and playing baseball?
It may have something to do with
the levels of testosterone in their mother's body during pregnancy,
say British researchers in a study published in the current issue
of Child Development.
The higher the level of maternal
testosterone, the more likely it is that girls will enjoy activities
typically considered male behavior, like playing with trucks or
guns, reports the study. Maternal testosterone levels don't appear
to affect boys' behavior, however, according to the study.
The researchers, from City University
in London, collected data on 679 children who were part of the
much larger Avon Longitudinal Study of Parents and Children, which
includes more than 14,000 children born in the early 1990s.
Blood samples were drawn from the
mothers to look for the presence of testosterone. Twenty five
percent of the mothers had blood samples taken when they were
between five and seven weeks pregnant; just over half had blood
drawn sometime during weeks eight through 24, and the final quarter
had their blood drawn sometime after 25 weeks of pregnancy.
When the children were three and
a half years old, the researchers had their mothers or primary
caregivers complete a questionnaire to measure how often a child
played with gender-specific toys, games or activities. Each question
was scored on a five-point range of how frequently a child engages
in a particular gender-specific behavior, from never to very often.
Low scores on the questionnaire indicated more typically feminine
behavior, while higher scores represented more male-oriented behavior.
The researchers also had the children's teachers complete the
questionnaire for comparison.
After controlling the data for
such factors as maternal education, the presence of older siblings,
a male partner living with the mother in the home, and how closely
the parents followed traditional gender roles, the researchers
found an association between maternal levels of testosterone and
the way girls behaved at preschool age. The higher the levels
of testosterone in pregnancy, the more likely girls were to score
high on the questionnaire. They found no association between boys'
behavior and mom's testosterone levels.
The researchers suspect there may
be several reasons for this. One is that boys naturally have higher
levels of testosterone prenatally and after birth, and so wouldn't
be as affected by changes in maternal levels of this hormone.
Another is that boys are more encouraged to behave in male gender-specific
ways, and discouraged from typically female activities. For example,
while many parents would be fine with their daughter playing with
trucks, some parents might discourage their sons from playing
"There's a long history of
debate on the relative importance of nature or nurture [in the
development of children]," says Dr. Charles Goodstein, an
associate professor of psychiatry at New York University School
of Medicine and the president-elect of the Psychoanalytic Association
of New York.
And, he says, this study would
seem to add credence to the nature side of the debate because
it appears that hormone levels in the mother can affect a child's
later behavior. But, he says, this study is only a beginning and
that the nature vs. nurture debate will probably never be resolved.
"It's hardly ever nature or
nurture. It's usually both," he says. "Simply because
we inherit a genetic makeup doesn't mean our life is set in stone."
What To Do
To read more about the nature vs.
nurture debate, read this article from NOVA,
a Public Broadcasting Service (PBS) program.
For more information on testosterone
in women, go to DrDonnica.com.
Reference Source 101