There's a gender gap lurking in your milky boobs. And the advantage goes to the boys.
Psychologists Nancy Segal and Satoshi Kanazawaas analyzed data from a
Longitudinal Study of Adolescent Health in the US. What they found was that the quality of a
mother's breast milk changes depending on the sex of a child.
results of same-sex twins and opposite-sex twins, Segal and Kanazawaas
concluded that a mother with different sex twins is not able to individually
cater to each child while breastfeeding both children at the same time. Their
analysis also suggests that mothers of boys produce heartier, more nutritional
breast milk than those who have girls.
In an article
published on The
New York Times website last week, Segal and Kanazawaas said that
“Breast-fed same-sex twins were indeed either slightly taller or substantially
taller than breastfed opposite-sex twins,” and that “Same-sex twins were, on
average, nearly one inch taller than their opposite-sex counterparts.
Similarly, same-sex twins were substantially heavier than the opposite-sex
twins except during the first measurement period. The same-sex twins were, on
average, 12 pounds heavier than the opposite-sex twins.”
Although latest theories
may leave moms scratching their heads for a minute, it isn't the first time the
debate over gender bias breast milk has come up. In 2014, Katie Hinde, an
evolutionary biologist at Harvard University argued that "Mothers are
producing different biological recipes for sons and daughters."
She went on to
say, "It's not yet clear why human mothers produce such different milk for
their babies. It could be adaptive in that it allows mothers to give more milk
to daughters which is going to accelerate their development and allow them to begin
reproducing at early ages."
Of course, this is all ignoring the fact that Hinde’s study was centered on the milk production of cows. Still, it was her belief that the stage is set for humans while a baby
is still in utero. By having a better understanding of how a mother's milk
catered to the individual sex of infants, she hoped to assist hospitals in
finding better matches for donated breast milk.
But the question
remains: Is a mother's breast milk gender bias? According to Segal and
Kanazawaas, it most certainly is. Their findings will be published in the
April edition of The Journal of Experimental Child Psychology.
“To the best of
our knowledge,” they argue, “ours is the first study to demonstrate that there
are observable physical consequences of sex bias in human breast milk.”
While skeptics dispute
the controversy surrounding their hypothesis, nursing mothers around the globe
will unite in confusion and await confirmation. Until then, their infant boys
and girls will have no other choice but to suck it up—as is.