The secret ingredient behind doting dads
A natural shot of female estrogen appears to
jump-start nurturing spirits in new fathers
2007 04:30 AM
For Father's Day, this "guy"
deserves a really expensive tie – though he'd
probably just chew it up or sleep on it.
The hamster in biologist Katherine
Wynne-Edwards' lab is such a doting dad that he
actually plays midwife at the birth of his many,
He helps pull them out of the birth
canal; he cleans them up once they're out. He even
tidies up (well, eats) the afterbirth placenta at
the end of the delivery, reports Wynn-Edwards, who
works out of Queen's University.
And by studying such rodent
behaviour, scientists are hoping to figure out just
why and when a peculiar physiological change occurs
in new or expectant fathers of the human variety.
"There are hormonal changes in men
when they become fathers," says Wynne-Edwards, whose
work is funded by the Canadian Institutes of Health
Research. "Those specifically are an increase in
(female) estrogen, a temporary decrease in
testosterone, and an increase in prolactin, which is
a hormone associated with the nursing process."
New dads need not worry, however,
about developing breast tissue or losing their
beards, adds Wynne-Edwards.
She says the spikes and dips are
small in terms of the entire male hormone balance,
and that the levels in new fathers remain well
within the typical ratios seen in most men.
Still, the changes are pronounced
enough to easily register in saliva samples.
And they could be playing an
important role in how welcoming and attentive dads
are to their newborn offspring, Wynne-Edwards says.
She points out that previous
research has shown the magnitude of the hormonal
shift is associated with the intensity with which
fathers are affected by their baby's presence.
The more pronounced a father's
reaction to his child is, the greater that shift is
likely to be, Wynne-Edwards says.
But regardless of the degree of the
hormonal flip-flop, it's not likely a primary driver
of the nurturing instincts that men may exhibit, or
the intensity of their fatherly involvement.
Instead, Wynne-Edwards says, the
hormone alterations likely contribute to the
psychological receptiveness of men to their infants.
"The hormones just make it easier or
harder for certain kinds of responses to come out.
"There is no prospect anywhere on
the horizon," she continues, "of a (hormonal)
treatment that will turn a man into a doting
According to Wynne-Edwards, no one
knows exactly when or how the hormonal shift takes
place – hence the current hamster studies.
But in the end, work in the area
helps show that testosterone is not the be all and
end all of men's hormonal reality.
"One of the benefits of this
research," she says, "is that it teaches us that
testosterone in not the measure of a man.
"In fact, estrogen is likely to be
an important hormone in men, just as we are growing
to understand that testosterone is going to be an
important hormone in women."