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Context and Variation


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The Duggars Demonstrate Life History Trade-Offs Around Quality Versus Quantity of Offspring

The views expressed are those of the author and are not necessarily those of Scientific American.


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A picture of the Duggar family (public domain).

Back in the day, when many anthropologists assume we were all egalitarian foragers living off the land, women may not have thought on how many offspring they wanted. Contraceptives and abortifacents have likely been with us a very long time, yet various environmental stressors probably suppressed reproductive function enough of the time that this was rarely necessary. Instead, babies happened. I’m sure many women were quite aware of how and why they happened, but with several years in between each one, cooperative breeding and play groups, overlapping dependent offspring was possible.

But of course, environments vary, and foragers may live in marginal or energy-rich environments. Some are partial agriculturalists or pastoralists. Some are able to hunt and fish as well as gather. And so there was, and is now, plenty of variation in interbirth intervals, or the length of time between births.

In a broader sense, the timing of pregnancies are an interesting way to study life history trade-offs. For instance, one may choose to have many offspring, place them close together and allocate less resource to them, or one may choose to have only a few offspring, spread far apart. This is a classic quantity versus quality trade-off question, and we see trends in these trade-offs within and between species, but also in humans, and even among different cultural traditions. It’s an interesting instance where culture can have a very real effect on one’s physiology.

Compared to other species, humans tend to choose quality over quantity. Human babies take a lot of energy to make and feed, and because of our slow life histories, long learning periods and late pubertal maturation, they are dependent on their parents for food and resources for decades. Offspring that are still asking for handouts well into their twenties, when their primate kin have become independent before turning ten, are not conducive to life history decisions towards quantity of offspring. Even with cooperative breeding and the trading of food and labor that occurs within human societies, human babies are costly, and under some conditions even dangerous.

And so after Tuesday’s announcement that the Duggars are expecting their twentieth child, I decided to read up on them, not having watched more than one or two early episodes. To offset their high reproductive output, the Duggars do seem to have significant resources in terms of an enormous house and a fair bit of money from Discovery Channel, the folks who run TLC, which is the cable channel that the Duggar family show is on. And, at least according to Wikipedia, they have a fair bit of sibling care: older siblings are assigned to younger siblings as mother’s helpers. This is consistent with what we see in some other forager populations like the Pumé: there, we see women give birth relatively young, but the mother’s younger siblings contribute to the offspring’s care to offset the costs of early reproduction (Kramer 2005).

But resources and cooperative breeding only get you so far, particularly when you are giving birth every year and a half for fifteen years. There is such a thing as maternal depletion syndrome. Maternal depletion syndrome comes from the depletion of energy stores and micronutrients (such as folate and iron) from having closely-spaced pregnancies, or living in a poor environment where it’s hard to have good enough access to resources to get food to replete these stores (King 2003).

Not having adequate time and nutritional resources to replete those stores can lead to major health concerns. For the mother, maternal depletion syndrome can mean not having adequate fat stores to feed the next fetus (Lassek and Gaulin 2006), and putting constraints on one’s reproductive output that can decrease the chances for having future children. It can also mean the mother develops nutritional deficiencies, or needs to allocate some of her stores to the fetus. Short interbirth intervals increase the risk of maternal death (Conde-Agudelo and Belizán 2000). And in some populations, the more babies a woman has, the shorter her life span; in others, costs manifest in other ways (Jasienska 2009).

For the fetus maternal depletion syndrome means the mother isn’t really that prepared to provide for the fetus. This can lead to fetal growth retardation (King 2003), to the point that the fetus needs to decide if its chances are better inside or outside the womb. Often, this also means a higher risk of preterm birth (King 2003; Klerman et al. 1998), as the fetus usually needs to take its chances outside where it hopes to get more energy from breastmilk.

This means that in addition to the nineteen, possibly twenty offspring the Duggars will have added to the planet, Michelle Duggar is very likely putting herself at risk with her many and closely-spaced pregnancies. In fact, Duggar experienced preeclampsia with her last baby and delivered three months prematurely as a result, with her daughter Josie weighing just over a pound at birth. Little Josie Duggar spent many long months in the Neonatal Intensive Care Unit of her hospital, and is very lucky to be alive.

Many people politicize and criticize the side of reproductive choice that seeks to limit reproduction through contraception and abortion, though limiting family size is something women and other primates and animals have done throughout our history. Perhaps it’s also time to consider the other end of the spectrum of reproductive choice and its consequences. This is not to politicize it – the Duggars have to make, be responsible for, and live with their own choices, and in general women have enough trouble getting to make reproductive decisions. But we need to realize that all reproductive decisions, not just those that limit the number of children, have costs and benefits.

References

Conde-Agudelo A, and Belizán JM. 2000. Maternal morbidity and mortality associated with interpregnancy interval: cross sectional study. BMJ 321(7271):1255-1259.

Jasienska G. 2009. Reproduction and lifespan: Trade-offs, overall energy budgets, intergenerational costs, and costs neglected by research. AMERICAN JOURNAL OF HUMAN BIOLOGY 21(4):524-532.

King JC. 2003. The risk of maternal nutritional depletion and poor outcomes increases in early or closely spaced pregnancies. The Journal of nutrition 133(5):1732S.

Klerman LV, Cliver SP, and Goldenberg RL. 1998. The impact of short interpregnancy intervals on pregnancy outcomes in a low-income population. American Journal of Public Health 88(8):1182.

Kramer K. 2005. Children’s help and the pace of reproduction: cooperative breeding in humans. Evolutionary Anthropology 14(6):224-237.

Lassek WD, and Gaulin SJC. 2006. Changes in body fat distribution in relation to parity in American women: a covert form of maternal depletion. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 131(2):295-302.

Kate Clancy About the Author: Dr. Kate Clancy is an Assistant Professor of Anthropology at the University of Illinois. She studies the evolutionary medicine of women’s reproductive physiology, and blogs about her field, the evolution of human behavior and issues for women in science. Find her comment policy here. Follow on Twitter @KateClancy.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Pugsley 4:38 pm 11/12/2011

    “cooperative breeding” hmmmm ….. tell us more about this. It sounds a lot like what we used to do in large crash pads back in the ’60s.

    “This can lead to fetal growth retardation (King 2003), to the point that the fetus needs to decide if its chances are better inside or outside the womb. Often, this also means a higher risk of preterm birth (King 2003; Klerman et al. 1998), as the fetus usually needs to take its chances outside where it hopes to get more energy from breastmilk.”

    Have the fetuses been talking to you again, Kate? ;-)

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  2. 2. Symbiartic.km 5:34 pm 11/12/2011

    Very interesting – I never thought of the health implications of multiple pregnancies so close together. Makes sense though.

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  3. 3. Patrick Clarkin 11:57 pm 11/12/2011

    Great post, Kate. And good timing. My students were asking about the Duggars so now I can point them here.

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  4. 4. Mceltix2000 5:31 am 11/13/2011

    Ah,the anti (white) children movement is still alive and well I see.

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  5. 5. jbairddo 10:49 am 11/13/2011

    Anti White children movement?, how about the “in 4 generations we’ll have a city movement”. The chances of the kids having the proclivity to each have 20 children are probably low to the point of zero, but let’s say it happens. By the time the mom and pop are great grand parents, their extended brood will be 160,000 strong (most cities aren’t that big, right?). Next one 3.2 million. Can I use the resources of 3.2 million people (minus 2 to the fifth power) because I only had 2 kids? On the surface this looks like it boils down to lots of kids vs not lots of kids, but the implications in a world with finite resources are huge. There are huge numbers of experts in vastly different fields who could have a “dog in this fight” if there were a debate about the social/economic issues as well as the scientific genetic issues.

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  6. 6. kkristina 4:43 pm 11/13/2011

    Considering that 60 million died in the last World War, and up to a billion in the history of the world, plus or minus 20 is not going to make a dent in our resources. Not until people are done playing their war games. Duggards would probably be national heroes in Russia, where the population still hasn’t bounced back after loosing 30 million in WW2, and every mother gets thousands of dollars for a baby to encourage population growth.

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  7. 7. Steve3 2:24 am 11/14/2011

    So …. how healthy are the kids and the mother? In the few fotos I’ve seen they all look quite small.
    Are any of the boys 6ft and 180lbs? The biggest looks 5′ 7″ and 125lbs.

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  8. 8. kclancy 8:49 am 11/14/2011

    Sorry folks, I was largely off the internet for the weekend so missed all your great responses.

    Pugsley, first: yes, the fetuses, they talk to me! Sorry for the hasty anthropomorphizing, it just seemed the easiest way to articulate the fetal point of view physiologically :) .

    As for cooperative breeding, there is lots and lots you can read on this. It’s a very hot topic right now, and I’ve been reading on it like crazy because I find it so interesting – it’s kind of an extension of what Kristen Hawkes started with her grandmother hypothesis. Sarah Blaffer Hrdy, Karen Kramer, Lesley Newson and countless others write on the topic. Hrdy has a few books and book chapters that should be available even without university access to journal articles.

    Mceltix, I struggle to see where in my post I was anti child, or anti white child. In fact, I made a special point to say that the Duggars are responsible for their own decisions and I have no desire to politicize them. The main point I wanted to make was that closely spaced births are bad for the health of mother and baby, and that a high frequency of offspring is dangerous too, which is the rhetoric offered around contraception and abortion.

    Steve3, I don’t know anything about the health of this particular family. I do know there is a pretty vast literature linking spacing of pregnancies, not necessarily number of pregnancies, to maternal depletion and adverse health outcomes for mother and baby. And based on the last pregnancy, which ended three months early in a very very premature baby that I imagine only barely survived, I am worried about this pregnancy. I don’t think the last one was a fluke but rather a symptom of having had 19 consecutive, closely spaced pregnancies. This last one has the greatest birth spacing yet, but I think it’s still under two years. Add that to her age, which is 45 or so, and I do worry for her.

    So, your question is an interesting one. I wonder what their birth weights were. I wonder if they would have been taller if the births were further apart or there were further births.

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  9. 9. Jerzy New 8:21 pm 11/14/2011

    @Kclancy
    Cooperative breeding comes at a cost, not? Children who help raising younger brothers and daughters delay their own reproduction, isn’t it?

    I noticed that in large families often one or more children is sick, gets some sad accident, goes alcoholic or another way doesn’t reproduce. So the large fecundity is cancelled by low fecundity in the next generation. Indeed, it would be interesting for anthropologists to see if tradeoff quality-quantity of offspring doesn’t show in humans this way.

    It also explains why narratives like “Bell curve” doesn’t came true centuries ago.

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  10. 10. Ehkzu 12:47 am 11/15/2011

    re:

    Comment #1
    Pugsley, the author was speaking metaphorically. Or did you know this and were just trying to be funny?

    Comment #4
    Mceltix2000, I put it to you that you are not a Scientific American reader but was directed to this site by some right wing blog. Right wing blogs do this frequently, I believe, thus bedeviling Scientific American forum with anti-evolution &/or anti-abortion &/or fundamentalist &/or anti-global warming acknowledgement &/or overpopulation denial fruitcakes.

    Usual it’s useless to cross swords with such folk because they don’t understand the underpinnings of science–analytic, empirical reasoning, scientific method, statistical probability–and thus treat scientific propositions as tribal battle cries.

    Scientifically trained people waste countless hours rebutting knuckle-draggers’ claims on this forum, Amazon.com science forums, & elsewhere.

    Comment #6
    kkristina, credible estimates have put the amount of land needed to sustain our planet’s 7 billion humans at their current level (including the 1 billion who are starving) at 1.4 Earths. That is, Earth’s current population is not sustainable. There isn’t enough arable land and potable water supplies, and even super technology can’t overturn the laws of physics.

    You excuse the Duggars’ huge family by saying Russia is losing population. You do realize that there are more people involved than Russians and the Duggars, right? On Earth as a whole the human population is increasing, births against deaths, at a rate of over 140 every minute. All the world’s 20th century wars are also a drop in that bucket.

    The Duggars are a drop in that bucket, but of course one thing they do on their TV show is proselytize on behalf of their ideology, which is one of unlimited reproduction (also the philosophy of cancer BTW).

    And the Learning Channel never questions this ideology, neither on the Duggars’ show nor elsewhere. There’s no show there about a couple who decided not to have any kids.

    http://www.blogzu.blogspot.com

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  11. 11. Jerzy New 5:56 am 11/15/2011

    @Ehkzu
    It is always pleasant to rebunk science myths propagated by ignorance.

    You may be interested that:
    - Estimate that given human population needs so much arable land, resources etc. ignore increase of agricultural productivity, energy efficent technologies etc.
    - Population growth is LOCAL problem. People from overpopulated regions in Africa or Asia cannot emigrate to depopulating Europe, USA etc.
    - USA has a problem with falling birthrate, not growing birthrate. Accept it. USA currently maintains its population only by immigration, and it is negative to Third World countries, because it sucks out most educated and productive people.
    - Welfare of people in Third World countries depends more on economic situation influenced by USA. For example, a rush for biofuels caused by hasty climate change policies, pushed food prices high and made millions in tropical countries starve.
    - What TV in America preaches has no direct effect on behaviour of people in tropics. People in Africa don’t watch Learning Channel.

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  12. 12. Ehkzu 8:39 pm 11/15/2011

    @jerzy new
    The problem with it being “pleasant to rebunk [sic] science myths propagated by ignorance” is that the common human shortcoming of hubris makes it also feel pleasant to think you’ve debunked the remorseless truths revealed by science when you’ve done nothing of the sort.

    I find this failing especially common among educated ideologues such as, in this case, Roman Catholics who think they’re intellectuals because they’ve acquired a smattering of erudition, but which does them and us no good because that erudition is the hapless dog being wagged by the tail of their foregone conclusions.

    Consider jerzy’s assertions:

    1. We have no overpopulation problem because technological advances will feed us all, not matter how many of us there are.

    Reply: Unfortunately, technological advances have been frequently used for quick gains at long term cost. For example, the introduction of modern explosives to SE Asia via WWII resulted in the postwar epidemic of reef bombing which continues to this day. Bombed reefs support almost no life and prevent the formation of solid hard coral reefs atop the rubble, so even when some recovery occurs, it’s not the equal of what was lost. This has resulted in food fish populations collapsing in that part of the world.

    Technology is being used to overpump porous aquifers worldwide. Overpumped aquifers collapse–permanently, and then the wells run dry. Water can be stored in other ways, but only at enormous cost, and has not been able to keep up with the collapse. Likewise, desalinization plants plants can produce fresh water from salt water, but again at enormous cost and in no way able to keep up with the demand of exploding populations. Ultimately the world has X amount of water. Our melting glaciers–thanks to global warming–are raising sea levels. These will drown huge coastal areas currently full of people and farmland, and that farmland will vanish. Even intact land near coastlines is losing its agricultural capacity due to saltwater intrusion into the water table.

    Technology has made it possible to quickly destroy whole marine ecosystems via trawling. Fishing fleets from countries that have destroyed their own coastal ecosystems range around the world destroying others. Thus you have, for example, Taiwanese and Portuguese fishing fleets (among others) cleaning out the coastal waters of Somalia and other countries unable to defend themselves from such intrusions.

    American agricultural technology, putatively the pinnacle of world agriculture, is cantilevered over the abyss. Agricultural runoff has polluted major waterways and water tables (especially around pig/cow/chicken farms) and produced a gigantic plume of toxic water 150 miles long in the Gulf of Mexico, in which nothing lives. Major growing areas like California’s central valley–the breadbasket of the country–is grappling with growing salinization of the water table because the area is an ancient seabed and irrigation is bringing the long-gone sea’s salt deposits into solution in the water table.

    I could go on for hours. The world’s green revolution in food production/distribution/storage technology that started after WWII did greatly increase the world’s food supply. But believing that will go on forever–and that it can keep pace with the growth of our human population–is akin to the belief people had in the 1990s that their home value would always keep increasing.

    All the green revolution did was buy us a few decades in which we had the opportunity to get our fecundity under control. That didn’t happen except in the rich countries, and now we’re running on empty.

    2. “Population gowth is LOCAL problem. People from People from overpopulated regions in Africa or Asia cannot emigrate to depopulating Europe, USA etc.”

    Huh? That’s EXACTLY what’s happening. Most of the US population growth for the past 40 years has been from immigration. Ditto Europe. Hence the riots in Muslim ghettos surrounding Paris, argy-bargy in the UK involving conflicts between locals and immigrants from the Caribbean and MidEast and India. Who do you think bombed the subways there–and the trains in Spain–and murdered a Dutch filmmaker–and drove Danish cartoonists into hiding?

    The United States’ Latino population was .5% of the total in 1940–now it’s over 14%, largely from illegal immigration, several amnesties, and the children of those illegals. And America also has received very large numbers of immigrants from Asian countries such as China, India and the Philippines.

    Perhaps you forgot the existence of ships and airplanes.

    3. “USA has a problem with falling birthrate, not growing birthrate. Accept it.”

    First, you presume a falling birthrate comprises a problem. Why? The population of the USA has more than doubled since 1950 and nearly quadrupled since 1900. Suppose our population declined to “only” the 151M we had in 1950. Nobody in 1950 was grieving about “only” having 151M people here. We didn’t have freeways yet, but if we had they wouldn’t be jammed for many hours each day.

    Second, despite a birthrate somewhat below replacement rate, our population is exploding due to the highest immigration rate of any industrialized country.

    Such that by 2050, at current rates of birth and immigration, the USA will have 439 million people–half again as many as we have now, and not spread around the country but mostly jammed into our metropolitan areas.

    If we stopped all immigration and we wanted a constantly increasing population, we’d only be able to create that increase by criminalizing all forms of birth control. Women with rights don’t have scads of children.

    Of course as the doctrinaire Roman Catholic I suspect you are, that would be fine with you. In countries under Catholic control, abortions are outlawed even when the mother will die without it, or the person is, say, a 10 year old child raped and impregnated by her stepfather.

    However, this is a possibility in the USA. By 2050, due to most immigration being by obedient Catholics, we’ll have a Catholic majority. And then women can enjoy the tender mercies of the Church Universal and you can get the laws you evidently desire.

    As for a brain drain from the third world–that’s certainly the standard European America=Satan viewpoint.

    But consider specifics. I used to know a Rwandan immigrant. He was a mathematician with a PhD. He was also a Hutu. His wife was a Tutsi. Had they stayed in Rwanda, both–and their children–would probably have been murdered in the Rwandan genocide. And even without the genocide, all he probably could have done with his PhD in math in Rwanda was teach arithmatic in an elementary school.

    I’d wager that a large number of the drained brains had no opportunity to use their brains back in the Auld Sod.

    And for some countries our psycho immigration policies let them solve their overpopulation/social services problem by outsourcing it to us. That’s what Mexico has done. We aren’t getting its doctors and engineers. We’re getting its semiliterate peasants. Courtesy of Mexico’s population quintupling since 1940, from 20 million to over 100 million–half living in poverty. It can’t feed, house or employ all those people. So it encourages them to move here, telling them the Southwest is really part of Mexico anyway (tell that to a Navaho).

    4. “Welfare of people in 3rd World countries depends more on economic situation influenced by USA.”

    The primary source of suffering by third world peoples is Third World governments–mostly kleptocracies that enrich a tiny ruling class at the expense of everyone else.

    Second is not adopting China’s One Child policy, &/or adopting the Catholic Church’s moronic “condoms are murder” policy. Take Haiti. Its population has more than tripled since 1950, and Haitians have chopped down 97% of the country’s trees for firewood, turning Haiti into a semidesert, while the Dominican Republic, on the same island, has abundant forestation due to an elightened government. Though it also has a severe illegal immigration problem thanks to Haiti.

    Third is, the governing kleptocracy selling the country’s natural resources to China (especially Africa and SE Asia). And ranchers burning down the forests for ranchland. And rich locals collaborating with foreign outfits–often Chinese, but also from most or all of the industrialized countries–including America–in illegally logging the forests and mining for gold and other minerals in the most polluting ways possible. And trawling fleets from Taiwan, Japan, Portugal and other countries causing local fish stocks to collapse.

    Fourth is drug production and trade caused by organizations like the Catholic Church and various right wing political parties persuading rich countries’ governments to criminalize adult drug use. If we wanted to do the Third World a huge favor we’d legalize narcotics.

    5. “What TV in America preaches has no direct effect on behaviour [sic] of people in the tropics”

    True, the Duggars’ “Quiverfull” movement insanity isn’t on TLC in the tropics, but American evangelical churches are highly active in the tropics. Our driver in Sulawesi was a devotee of Benny Hinn television ministries, for example. And they’re all just this side of the Catholic Church in their devotion to promoting population growth by opposing abortion and sex education. American televangelists are highly active in the third world.

    http://www.blogzu.blogspot.com

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  13. 13. Jerzy New 8:27 am 11/16/2011

    @Ehkzu
    I don’t see what explosives have to do with food production, for example, and most of your lengthy ramble seems fallacy.

    For example, immigration to Europe and USA is too small to make a dent on population of tropical countries as a whole. Your numbers simply don’t add up. In contrast, it becomes significant when you take only highly educated, young sector of population – countries most valuable human resources.

    And more common misconception – that Catholic Church has a role in world’s overpopulation. Catholic countries in Europe, like Italy and Poland have birthrates below repllacement level, and lower than European average. Countries with the highest birrthrate are animist and Muslim, so the Church simply has no say there.

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  14. 14. kclancy 9:51 am 11/16/2011

    So, you two have certainly gone off and are having your own conversation about a complete tangent on this post. And that’s fine, encouraged even! But I have to butt in for a moment: what is this about Poland having a birth rate below replacement? Can you provide a source for this? Because I do fieldwork in Poland, and it’s still a very Catholic country that celebrates making lots of babies. I work in the village with the highest birth rate in the whole country, with a significant minority having around 12 children.

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  15. 15. Ehkzu 4:09 am 11/17/2011

    kiclancy, you concluding your piece by saying:

    “all reproductive decisions, not just those that limit the number of children, have costs and benefits.”

    Your article talked about the cost to both mother and offspring. My tangent was to discuss the cost of large families to the planetary ecosystem.

    You didn’t mention the fact that the Duggars belong to a Christian fundamentalist movement called the “Quiverful” movement, that advocates having as huge a family as possible, never using any form of birth control including abstinence. So theirs isn’t just a personal decision but an ideological one–an ideology shared, functionally, by conservative Muslims and Hindus as well, given the average size of families of both persuasions.

    So I believe it is germane to talk about the societal consequences of the Duggars’ “family planning,” as well as the personal ones you discussed, since they themselves advocate everyone adopting their approach, and they use their TV show to advocate it as much as TLC will let them.

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  16. 16. Jerzy New 6:29 am 11/17/2011

    @kclancy
    Easy Wikipedia search puts Poland near the absolute bottom of fertility rate: 1,21 children per couple.

    http://en.wikipedia.org/wiki/List_of_sovereign_states_and_dependent_territories_by_fertility_rate

    Maybe Poles you live among like lovemaking for fun, not for babies?

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  17. 17. sars1 3:04 pm 11/17/2011

    Having not read the details of the study, I wonder if there is much of a difference in the maternal depletion syndrome in third world countries and western nations. I would imagine that in the US if you are getting adequate pre-natal care, including taking vitamins, and eating a healthy diet you would not have the same concerns as you would in an environment where you would not have the same access to medicine and nutrition.

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  18. 18. rrocklin 2:24 pm 11/18/2011

    “Little Josie Duggar spent many long months in the Neonatal Intensive Care Unit of her hospital, and is very lucky to be alive.” Who do you think paid for this very expensive care? The public paid for it through higher health care costs. Their behavior is irresponsible because of the cost to society and environment. The Discovery Channel is helping to enable them and is glorifying their behavior. Shame on them.

    Link to this

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