Causes of infertility mysterious
Children of Men evokes question of how an infertility epidemic could arise
Social unrest has turned Europe into a veritable war zone, nuclear fallout adds to the suffering in Africa, and Britain's government is an authoritarian menace.
Take all that misery and add a global fertility pandemic and you've got the ultra-bleak vision of the future from the new movie, Children of Men.
Of all the terrible menaces in this dystopian possible future, the specter of not being able to procreate is by far the worst. Humanity's days are numbered, but save for a miracle. No explanation is put forth by the movie for the sudden inability of women to conceive. The closest thing we get is a well-delivered joke from Jasper (Michael Caine) in which humans dine on baby-delivering storks.
Moviegoers may feel sold short by this tidbit of critical information being held back. But the truth is, the main infertility problems faced by humanity today are equally shrouded in mystery – one that light has been shed on only very recently.
The infertility epidemic
About one in eight women in the United States had difficulty getting pregnant and carrying a baby to term in 2002, according to the National Center for Health Statistics. Half of these women were afflicted with polycystic ovary syndrome – in which a cyst takes the place of a healthy ovary and blocks a woman's normal menstrual cycle.
Aside from being caused by a combination of environmental and genetic factors, scientists couldn't specifically say what caused this syndrome - until last month.
An American Physiological Society study completed in December 2006 points to a genetic marker for the condition. In a study that compared 146 women with the syndrome to 606 controls, it was found that certain variants of the gene Calpain-10 could be to blame.
The gene is the same one that spurs adult-onset diabetes. This makes sense, since women
with this syndrome are more likely to develop diabetes and be overweight.
The infertility disease
Another 40 per cent of infertile women have a non-infectious disease called endometriosis. The disease causes fragments of the uterine lining (the endometrium) to be errantly implanted by the body in other areas of the pelvis.
A University of North Carolina School of Medicine study found this disease likely causes infertility because crucial proteins are absent from the uterus. Late in the menstrual cycle, certain proteins are present so an embryo can attach itself to the uterine lining.
Despite this insight into endometriosis from the 2000 study, the cause of disease is not yet known.
Stress a key factor
In other cases of infertility, it is not a mysterious disease to blame but everyday stress. A 1996 University of Washington study on wild baboons showed stress was a major hurdle to becoming pregnant.
Of all species, a human's reproductive system most closely resembles a baboon's. That's what inspired researchers to sample hormone levels of the fecal matter of 30 Tanzanian baboons.
They found that baboon females in better social status were able to conceive more often. They attributed this to a physiological response in those baboons with a lesser social status.
The lower a baboon was in the social hierarchy, the more stress they experienced. The more stress they experienced, the less dense were their receptors that allow the progesterone hormone to bind and elicit its embryo-nurturing response.
The mystery lives on
These infertility problems are not insolvable. Despite the lack of knowledge of how they're caused, modern medicine has treatments to allow women afflicted with them to conceive. The most extreme and controversial being in vitro fertilization.
Yet one in five women who experience infertility problems never learn the cause of their problem, according to the American Society for Reproductive Medicine. Infertility is becoming a more widespread problem in North America, where women are waiting until later in life to have their children.
The older a woman is, the less eggs she'll produce – especially past 35.
But for the most part, humanity can breathe easy. Our world is nowhere near the barren future of 2027 depicted in Children of Men.
