Who's really the weaker sex? Male biological frailties challenge stereotype

Early chemical exposures that target boys' hormones and brains leave them more vulnerable to life's hazards

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      The following article was originally published by Environmental Health News

      We can, thankfully, remove one threat to the future existence of the human male from our worry list: the male Y chromosome, after dwindling from its original robust size over millions of years, apparently has halted its disappearing act.

      But don’t start cheering yet. Contrary to cultural assumptions that boys are stronger and sturdier, basic biological weaknesses are built into the male of our species.

      These frailties leave them more vulnerable than girls to life’s hazards, including environmental pollutants such as insecticides, lead, and plasticizers that target their brains or hormones. Several studies suggest that boys are harmed in some ways by these chemical exposures that girls are not.

      It’s man’s fate, so to speak.

      Males are disappearing

      First of all, human males are disappearing. Mother Nature has always acknowledged and compensated for the fragility and loss of boys by arranging for more of them: 106 male births to 100 female newborns over the course of human history. (Humans are not unique in this setup: male piglets, as an example, are conceived in greater proportion to compensate for being more likely than female piglets to die before birth.)

      But in recent decades, from the United States to Japan, from Canada to northern Europe, wherever researchers have looked, the rate of male newborns has declined. Examining U.S. records of births for the years between 1970 and 1990, they found 1.7 fewer boys per 1,000 than in decades and centuries past; Japan’s loss in the same decades was 3.7 boys.

      Boys are also more than two-thirds more likely than girls to be born prematurely, before the 37th week of pregnancy. And despite advances in public health, boys in the 1970s faced a 30-percent higher chance of death by their first birthday than girls; in contrast, back in the 1750s, they were 10 percent more likely than girls to die so early in their lives.

      Boys far more prone to autism, asthma

      Once they make it to childhood, boys face other challenges. They are more prone to a range of neurological disorders. Autism is notoriously higher among boys than girls: now nearly five times more likely, as tallied by the U.S. Centers for Disease Control and Prevention.

      They are more susceptible than girls to damage from very low-level exposure to lead. Yet another problem: boys also suffer from asthma at higher rates. There’s also a stronger link between air pollution and autism in boys.

      What is up here? Why do boys face such a burden of physical challenges?

      The answer is that the male’s problems start in the womb: from his more complicated fetal development to his genetic makeup to how his hormones work.

      Boys start out as girls

      The nine-month transformation from a few cells to an infant is a time of great vulnerability. Many chronic illnesses are seeded in the womb. In our species, the female is the default gender, the basic simpler model: humans start out in the womb with female features (that’s why males have nipples). The complicated transformation in utero from female to male exposes the male to a journey packed with special perils.

      When the first blast of testosterone from the Y gene comes along at about the eighth week, the unisex brain has to morph into a male brain, killing off some cells in the communication centers and growing more cells in the sex and aggression centers. The simpler female reproductive system has to turn into the more complex male reproductive tract, developing tissues such as the testis and prostate.

      Further, it takes a greater number of cell divisions to make a male; with each comes the greater risk of an error as well as the greater vulnerability to a hit from pollutants.

      Lack of backup chromosome a weakness

      On top of that challenge, the human male’s XY-chromosome combination is simply more vulnerable. The two Xs in the female version of our species offer some protection: in disorders where one X chromosome has a genetic defect, the female’s healthy backup chromosome can take over. But with his single X chromosome, the male lacks a healthy copy of the gene to fall back on.

      The X chromosome, which never shrank, is also a larger chromosome “with far more genetic information than the Y chromosome”, according to Irva Herz-Piciotto, a University of California, Davis autism researcher, “so there may be some inherent loss of key proteins for brain development or repair mechanisms in boys”. This is a clue to the higher autism rate among boys, she asserts.

      Females also have a stronger immune system because they are packed with estrogen, a hormone that counteracts the antioxidant process. “Estrogen protects the brain; it’s a no-brainer, pun intended,” explains Theodore Slotkin, professor of neurobiology at Duke University’s School of Medicine. “It repairs and replaces, even after neural injury.”

      Boys more sensitive to head injuries

      Low estrogen even leaves boys more sensitive to head injuries. The male brain “is simply a more fragile apparatus, more sensitive to almost all brain insults”, lead-poisoning expert Herbert Needleman told writer Julia R. Barrett of Environmental Health Perspectives.

      It’s the high levels of testosterone in the womb at critical times in gestation, according to British psychopathologist Simon Baron-Cohen, that are responsible for what he calls “the extreme male brain”—the kind exhibited by autistic boys—low in empathy, high in systematizing. And, in fact, recent decades of U.S. research do find unusually low estrogen and high testosterone levels among boys with autism.

      If the balance of hormones is out of whack in males, what made that happen? Researchers are coming up with some clues.

      Chemical exposure affects boys' IQs

      In the New York City neighborhoods near Columbia University’s Center for Children’s Environmental Health, families for years routinely sprayed their apartments with a popular insecticide, chlorpyrifos, until it was banned from household use in 2001. The researchers found that prenatal exposure to the chemical seemed to have more of an effect on reducing the IQs of boys than girls. Disruption of their male hormones may be the reason.

      “One possible explanation for the greater sensitivity of boys to chlorpyrifos is that the insecticide acts as an endocrine disruptor to suppress sex-specific hormones,” said study leader Megan Horton of Columbia.

      Similarly, pregnant mothers’ exposure to phthalates—used in making some vinyl products and toys as well as some personal-care products—has been linked to bigger changes in the behavior, such as aggression and attention problems, of their sons than their daughters. Phthalates also may feminize male genitalia.

      BPA causes hyperactivity, affects thyroid hormones

      Boys also seem to be more vulnerable to bisphenol A, an estrogenic substance used to make polycarbonate plastics as well as some thermal receipts and the linings of food and beverage cans. Boys, but not girls, exposed to higher BPA levels in the womb or during childhood had more hyperactivity, aggression and anxiety problems, according to a University of California, Berkeley study.

      In addition, pregnant women exposed to higher levels of the chemical gave birth to baby boys with lower thyroid hormones. No such effect was detected in the baby girls. No one knows what these lower levels may mean for the boys’ health because they remained within normal boundaries, but it could have important effects because thyroid hormones guide brain development.

      Fetal exposure the most harmful

      Some of these chemicals act like fake estrogens, others like fake testosterone, but both types seem to disrupt normal development. Animal tests show that a dose of these chemicals inflict the most damage when it hits a fetus. And, because of their biological vulnerabilities, it’s boys who may experience the most effects.

      Although not forgoing the push for fairness and equality, it seems wise to accept the scientific reality of male weaknesses.

      This likely won’t mean the end of men, but their vulnerability to environmental contaminants and diseases could have serious ramifications for the future of the entire human race unless we find ways to protect them from harm.

      Alice Shabecoff is the coauthor with her husband, Philip Shabecoff, of Poisoned for Profit: How Toxins Are Making Our Children Chronically Ill, Random House 2008, Chelsea Green, 2010. 

      Environmental Health News is a foundation-funded daily news service that also publishes its own enterprise journalism.

      Comments

      3 Comments

      What I think?

      Feb 20, 2014 at 11:36pm

      I think the gender who think's that the other gender is weaker, is the weaker gender.

      I am a man who agrees with gender equality but I have always felt that:

      Even though you women claim to want gender equality. You would not/ will not stop at equality. You will try to push further past it and take more than an equal share,( of power, of pay, of strength, of rights) you will try to take it all. And once that happens you will NEVER give back the chance for men to reach equal rights.

      okok, obviously all girls arn't like that. But all you preaching feminists sure are, you know it too but you won't admit it because it will ruin your plan.

      This article proves that mentaility.

      Who is the weaker gender? Who the F... cares?

      reach equailty again

      0 0Rating: 0

      JR

      Feb 21, 2014 at 11:50am

      As a woman, I completely agree that it does not matter who the "weaker" sex is. While I will admit that my male partner is physically bigger and some may say "stronger," it's problematic to make blanket statements that men by definition are stronger than women. This article is simply attempting to debunk the notion that women are "weak" beings - both physically and mentally - by exposing that men, too, have substantial weaknesses.

      As men read this article, that was written by a woman, perhaps now can feel and empathize what it is like to be told that you are the weaker sex, as if a) it matters, and b) your female counterpart has any authority to make these claims.

      Arguments of this article aside, I simply challenge readers of this to reflect on what it is like to consistently receive negative and hostile attention from others in order to establish and maintain authority over another group (especially in such a broad term as is sex and/or gender). For the male readers, did you feel personally attacked by these statistics/findings? Did you question why this information is relevant? Maybe you just got a glimpse into a woman's world, in that yes, this confrontational language and attention, based solely on your sex/gender, is F---ing annoying.

      0 0Rating: 0

      jla158

      Feb 26, 2014 at 5:05pm

      1, After the WW2 the sex ratio rose (more boys and less girls born than before). We don't know why. Then the sex ratio has been declined. It has been simple the reverse the the earlier trend. Actually in that countries the sex ratio isn't lower now than before the WW2. On the other hand this is the US, Japan, but not every country. For example in Italy and Spain the sex ratio nowadays is 106-107 which is as high as it was in the US after WW2. So the sex ratio isn't declining everywhere and where it is declining there was an increase after the WW2.

      2, She said that boys infant mortality rate was only 10 percent higher than girls in the 1750's and in the 1970's that was already 30 percent higher which is true but we are in 2014 and not in the 1970's. She forgot the fact that boys' infant mortality rate has been declining much faster than girls' infant mortality rate since the 1980's:
      http://www.pnas.org/content/105/13/5016.full
      That article was written in 2008, but the trend is the same nowadays, for example in 2012 the excess of male infant mortaly was record low again in the EU countries, that was only 17% higher than girls and not 30% higher like in the 70's.

      Boys are bigger in the womb and they more likely to born earlier stage of the pregnancy. This two facts leads to higher infant mortality rate. However those are less and less problems nowadays as the medical care improving.

      3, More boys affected by asthma but they are more likely to grow out of asthma than girls:
      http://www.telegraph.co.uk/health/2564089/Boys-are-more-likely-to-grow-o...

      There are more autistic girls but they aren't diagnosed, because they can hide (the society teaches boys to be wild and girls to be calm):
      http://www.autismdailynewscast.com/girls-are-being-under-diagnosed-with-...

      She wrote a lot of the insignificant thing to this issue (affects a small part of society) but only those which seems to be beneficial for girls. It is a double standard. She wrote about the advantages of the estrogen but nothing about the advantages of the testosterone. For example boys have higher testosterone level from birth that is why they have more muscle and they are physically stronger than girls.

      My opionons about this article:
      - distrotion of the facts
      - double standard
      - sexism

      0 0Rating: 0