People might assume that researchers who test drugs
and companies that make medicines take sex
differences into account. After all, we are
accustomed to lots of things being sex-specific.
There’s clothing created for females and bicycles
built for females. There are replacement knees
designed to accommodate not only females’ size but
also gait and weight distribution. Females,
unsurprisingly, are different than males.
Still, almost no one is paying attention to the fact
that sex matters on a cellular level.
Femaleness and maleness are more than the sum of an
individual’s genitalia. The difference is manifest
in our molecules—the very enzymes that metabolize
the drugs we take, for instance.
Mounting evidence around the globe reveals
differences in men’s and women’s responses to
pathogens as well as therapies, no matter whether
we’re looking at Zika, malaria, flu, lupus or heart
The mere fact that 80 percent of all autoimmune
disease patients are women should be a red flag that
women’s immune systems respond differently than
It’s time to rethink biological sex differences on a
very fundamental level. We need to design research
studies from the outset to compare the sexes by
making an a priori hypothesis that males and females
will be different.
Not a single vaccine is sex-specific.
The HPV vaccine, a beautiful preventive measure, is
an interesting example. It’s the only one I can
think of where dosage and schedule all are based on
trials for girls. And once we realized the vaccine
could protect boys too, we simply applied data
collected from girls to boys.
But now data about the HPV vaccine show a higher
antibody response in girls than in boys.
You might ask: If the response in boys is high
enough to protect them, who cares?
More and more of us do, in fact. The dogma—that sex
doesn’t matter—is changing.
If you survey the old data for measles and polio
vaccination, you’ll see that females suffered
mortality at higher rates with those vaccines too.
So at what point do we stop saying, ‘Well, with
malaria it was all due to chance’? Was it all due to
chance with measles? With the oral polio vaccine?
This isn’t just about vaccines. It’s also about
drugs that are widely prescribed for common
For example: Women metabolize zolpidem, the active
ingredient in sleep medications, more slowly than
That 2012 discovery came after two decades of women
overdosing on a drug known to significantly impair
driving—on the advice of their doctors.
In 2010, for instance, women experienced more than
two-thirds of all 64,000 zolpidem-related
In January 2013, the FDA warned that the recommended
dose for women should be halved, a change now
incorporated in the drug directions.
There needs to be more of that. Despite studies
showing that in women, a half dose of the flu
vaccine is as effective as a full dose and may cause
fewer adverse reactions, the FDA still recommends
that men and women receive the same full dose
How Being Male or Female Can Affect Your Health
For more information
Johns Hopkins Bloomberg School of Public Health