wow… are you serious ? (i mean that as an expression)
i did a bit of google searching and found this site:
http://www.babychoice.com/scientific_review.html
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In 1992 the Science university of Tokyo confirmed the Koltzoff V Schroder findings and recognised the ability to separate the sperm containing y and x Chromosomes by electrolyses.
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i’m amazed… i am so amazed… i was so clueless that such things were possible…
Here’s something to chew on:
Should it be done?
Spinning is apparently done for couples who want a child of a specific gender.
Is this a good idea?
Should people have the right to go to their local lab and “order” a boy or a girl?
Wouldn’t you expect more female infants?
It makes sense in evolutionary context,as females are reproductively incapacitated for nine months while males are free to impregnate.
This is all very fascinating - I am well aware of the bias against girls in much of the world, and all this discussion brings another question to mind - if these trends continue, and world population becomes significantly skewed toward males, wouldn’t this produce a precipitous drop in population within a generation or two? Fewer females = fewer conceptions - fewer births? Thinking out loud here, but I wonder how much of a bias would be required to significantly lower the birth rate?
Interestingly, even a significant drop in birth rate might not have that much effect on the survival of humanity. We’ve gotten very good (in industrialized nations, at least) at keeping our children alive long enough for them to reach maturity. If you listen to a nature show long enough, sooner or later the narrator will say how many of the newborns will die before maturity. The number is appalling by our standards: upwards of one-third for some predator species at the tops of their local food chains; as many as 90+% for sea turtles.
Here’s a couple of WAGs supporting the evolutionary benefit of the observed ratio (105/100):
(1) Male infant mortality is higher than female infant mortality. Modern day statistics do not apply because of the impact of modern medicine. What were the birth/survival rates 5000 years ago?
(2) In the days (long ago) when evolutionary pressures still drove human development the tribe with more males was more successful at hunting and was more able to defend/attack the water-hole.
Rather than dust off the papyrus to read the factoids on a 5,000 year-old copy of Ancient Egypt Today, you may as well set your sights a mere 100 or 150 years back (or look at some modern third-world countries) if you want to eliminate the statistical impact of modern medicine. For example, my great-grandmother had twelve children between ~1895 and ~1915, of which seven survived to adulthood, and this was in Montreal, a major city. Good solid statistics from the Napoleonic era onward should be easy to find.
Evolutionary pressures are still driving human development, though the issues are often more subtle than raw survival. What technologies survive are a matter of natural selection, just as beaver dams were. Improved living standards have prompted smaller family sizes in industralized nations, and that can have major impact on the social order of the species (an evolutionary impact if I ever heard one), though not enough to threaten its perpetuation.
The evolutionary advantage of having lots of male children is a bit of a stretch. Maybe it does mean that you’ll have more defenders of your family territory. Trouble is, the male children don’t become effective defenders until they start to put on serious muscle mass, which for humans kicks in at around 13. So if a man has lots of male kids, and they survive to maturity (a crapshoot in itself, see above point), they may be able to help defend their father’s territory while he continues to have kids? Tricky, when average pre-medicine lifespans might have been 40 years or less. By the time a man benefits from this XY-sperm surplus, he may be beyond his most fertile years and/or dead. An evolutionary benefit with such a long-awaited payoff may not be that useful. A five-percent chance of an edge 13 years from now? Yikes.
More likely, if I may suggest, is that the sperm cells are of different sizes and qualities by pure chance, and the gender ratios have been close enough so that there was no evolutionary pressure to evolve away it. We still have useless appendices simply because they don’t kill a conspicuous number of people before they can reproduce. We’re stuck with a lot of biological and anatomical features that now seem useless or annoying but barring genetic engineering, we’ll remain stuck with them because they’re simply not deadly enough for nature to take notice. A natural five-percent edge to male children doesn’t create a problem large enough to need solving. A fifteen- or twenty-percent imbalance, though, is something we’ll get to see in India and China in just a few decades. It should prove interesting.
There was an article in today’s paper that the sex ratio in China is up to 117 boys to 100 girls. I found this site, which seems to be an official site from China, (but what do I know? Here’s the home page) has some more figures:
1982: 108.5
1985: 110.9
1990: 111.3
1995: 115.6
2000: 116.9
Some more chilling statistics, the results for first born, second born, and third and higher:
1990: 105.2, 121, 127
2000: 107.1, 151.9, 159.4
There was an article about infanticide in China in a recent edition of Time magazine. Apparently there are now areas in China where the sex ratio is skewed 2:1 (boys:girls). This has resulted in marriages between first cousins and siblings because it is difficult and expensive to have women brought in from other towns for marriage. Imagine the effect that it will have genetically over, say, four generations. The people in those towns are already finding abandoned newborns with problems from the inbreeding - extreme retardation, etc.
I’ll get the date and page number from the magazine tomorrow when I go to work - the article’s certainly worth a peek.
About, oh, maybe 6 or 7 years ago, there was this big report on 20/20 about India and how they are killing off the next generation of women.
Apparently you can’t throw a rock there without hitting an ultrasound place … so if you’re preggers, you go in, and if you’re having a girl, you have an abortion.
At the time of the report, they had been doing this for like, 20 years … and I can’t remember how many girls had been aborted but it was unreal, in the millions. However as far as they knew only ONE boy, in 20 years, had been aborted, and that was an accident.
Give it another 20 years or so and India’s gonna have a BIG problem, no women to have any more babies.
It’s been years since this report aired but I think I’m remembering it pretty accurately.
Anyone else see it?
I think the birth ratios are due to higher male infant mortality, I’m pretty sure that’s the accepted explanation.
I did see a report on the India ultra-sound thing - not long ago - as I recall it was on 60 Minutes. Well, this might actually have a positive effect Not only will population decline in the areas where this (and other forms of male bias) are practiced, but if there is a severe girl shortage, it MIGHT actually make women more valued. I can only hope.
More likely it will make women more enslaved. There will be stronger social pressures for women not to work but have children. Their choices will be taken from them.