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Profits cost us cures

I know nobody here needs convincing that the free market doesn’t provide the best medical care for all. But it’s not just the care part that struggles. The real heart of medicine is cures and, best of all, preventing disease altogether. Profit-driven drug delivery actually hampers finding the best solutions.

I’d say the most insidious effect is how research gets shunted away from the really good stuff. That takes away benefits in the future, and we don’t even know what we’re missing. It could be the cure for cancer or a vaccine against the common cold. Maybe it’s something that makes childbirth feel like orgasm. (Contractions are contractions. It’s an interesting question why there’s such a big difference in felt sensations.) The point is we don’t even know.

And don’t even get me started on what’s painfully obvious: the fact that prevention can never be a priority in a profit-driven system. Read more »

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Biofuels: good, bad, and ugly

We’re hearing more and more about biofuels because they’re an alternative fuel (i.e. “good”), because they don’t increase carbon dioxide in the air (“good”), because they can be produced any time any where (“good”), they can be used in current cars (best of all), and are generally the solution to a zillion looming problems.

If it sounds too good to be true, that’s because it is.

The first problem with biofuels is figuring out what people are talking about. Ethanol from corn? Crop waste used in power plant cogeneration? Methane gas from landfills? Or composting toilets? Alcohol from cellulose? Fryer oil biodiesel?

The second problem is that “bio” doesn’t equal “good,” no matter how green it sounds. Some of these technologies are shaping up to be worse than our current oil-based one. The worst problems are at the production end, not during consumption, which makes it much easier to bamboozle rich-country consumers into thinking they’re helping the planet. We need to be aware of what different biofuels really mean before rushing into alternative energy “solutions” that are anything but.
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Female Genital Mutilation

It’s gone by other names, primarily female circumscision, as if it was nothing more than the male equivalent of removing the foreskin. It’s supposedly another one of those awful things that “can’t happen here.” Read the CNN report about the British, who may finally get serious about stopping the practice, and you’d never guess that tens of thousands of children suffer through the mutilation and its lifelong consequences right here in the good old U. S. of A.

Why the bizarre silence? Because it’s a “cultural issue,” you know. The approved term is now female genital cutting. Some people felt that the term “mutilation” was culturally insensitive.

For those occasions when somebody starts suggesting that this is a “cultural” matter, consider the facts.

First, an anatomy lesson, developmental anatomy, to be precise. The tissues in males and females come from the same embryonic structures. They just follow a different path of development. The biologists’ term for that is homologous structures. The types of nerves and arousal present in the different male and female structures are much the same, with some differences I’ll note below.
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Gene Scans and Single Payer Health Insurance

At first glance, an avantgarde diagnostic technique might seem to have little in common with a beancounter topic like insurance. The first glance couldn’t be more wrong.

Gene scanning means you’ll soon be able to find out just how susceptible you are to a whole series of diseases. And so will other people.
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Global warming: links to rebut deniers

With the Live Earth concerts rolling and the wingnuts whining in the woodwork, I thought it might be useful to give the Shakers one of the best links I’ve seen for the facts about global warming. Just in case you find yourself contending with wingnut talking points. (The acronym being WTP, interestingly enough.) The New Scientist (May, 2007) had an excellent and complete rebuttal of WTPs: Climate Change: A Guide for the Perplexed. They cover everything.

From what I’ve seen without looking for it, the wingnuts seem to have moved away from the “hockey stick graph is false” bullshit. I guess because the new facts, with that nasty liberal bias they have, insisted on landing higher and higher up the curve until they got into the handle and then blew right off the top of the graph. (I’m exaggerating, but not by much.)

Now one favorite line is, “The glaciers are too NOT melting. Or if they are, only a bit. Or if it’s a lot, then it has nothing to do with global warming.” … Read more »

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Tuberculosis: the problem we could have avoided

People went on red alert about SARS, where the fatality rate was approximately 10%. Bird flu doesn’t even spread between people (yet), but we’re on red alert about bird flu. Don’t get me wrong. Prevention is way better than cure. But it would make sense to deal with actual current threats before panicking about possible ones.

Tuberculosis is a much bigger problem than SARS, and it’s here, now, and killing millions. Untreated TB has a fatality rate of around 55%. TB treatment in the days before drugs reduced that rate to around 30%. In developed countries, with anti-TB drugs, the fatality rate was around 7%. (TB stats from the CDC.) Most of the current fatalities worldwide are people who had ordinary TB and couldn’t afford the cure. From a callous perspective, that’s not a problem in developed countries. But the drug-resistant strains that evolve in people who can’t or don’t take the full course of treatment is everybody’s problem.

As if that wasn’t bad enough, drug-resistant TB just took a turn for the worse.

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Fraud, funding, and science

Everything from health to wealth depends on science in the modern world, so, obviously, scientific results had better be rock-solid. And yet honesty in science is enforced by what amounts to a gentleman’s agreement, and the penalities for breaking it are nothing more than career damage. Contrast that to financial dishonesty. Its only direct effect is loss of money, but it is regulated by hundreds of laws, and the penalties include jail time.

Scientific honesty has been in the spotlight recently because of fraud in stem cell work by Dr. Hwang in South Korea. Science, which is the premier forum for publishing scientific results together with Nature, plans to have high profile work more stringently reviewed. This is good and necessary, but it only scratches the surface.

Fame and fortune in some fields of science only mean that the corrosive influence money on the scientific process is more noticeable. It’s present everywhere, and is arguably more insidious when it’s invisible. Dealing with that influence at all levels would be more effective than trying to promote stopgap honesty at the top. Read more »

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Advertising: what you don’t know gets you

Advertising is a nuisance. We tune that stuff out. Right?

Well, yes. Right. Which turns out to be exactly what gives it its power. If we didn’t tune it out, it wouldn’t work.

A while back, 1997 to be precise, there was an article in Nature showing that subliminal messages (i.e. below-the-threshold messages, tuned-out messages) influenced product choice more than conscious ones (via Mindhacks).

This study was done by Adrian North and colleagues from the University of Leicester. They played traditional French (accordion music) or traditional German (a Bierkeller brass band – oompah music) music at customers and watched the sales of wine from their experimental wine shelves, which contained French and German wine matched for price and flavour. On French music days 77% of the wine sold was French, on German music days 73% was German – in other words, if you took some wine off their shelves you were 3 or 4 times more likely to choose a wine that matched the music than wine that didn’t match the music.

Did people notice the music? Probably in a vague sort of way. But only 1 out of 44 customers who agreed to answer some questions at the checkout spontaneously mentioned it as the reason they bought the wine. When asked specifically if they thought that the music affected their choice 86% said that it didn’t. The behavioural influence of the music was massive, but the customers didn’t notice or believe that it was affecting them.

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Males prefer older females

Not among humans, of course. This is among chimps, as reported in the Nov 25th, Science News (sub. reqd.), based on work done by Martin N. Muller and others reported in the Nov 21 issue of Current Biology (abstract).

(I’m not sure why this is big news at this point. I heard much the same thing in primate anthropology classes I took decades ago. This has been observed repeatedly.)

Muller’s explanation, though, is what led to this post, just as soon as I stopped hooting with disbelieving laughter. From the SciNews article, “…nothing beats the sex appeal of an old female chimp. If that preference makes no sense to the average human male who’s entranced by young, smooth-skinned women, it’s because the mating game has evolved in different directions in chimps and in people…. People usually form long-term sexual partnerships. Men thus tend to look for women’s physical signs of youth, which signify childbearing potential for years to come….”

This is the first time I’ve seen one of these just-so story explanations based on male monogamy. The very first time. I mean why didn’t I think of that? Of course human males have to go for young women, because after they’ve found their one and only, they’ll never ever have sex with anyone else. If they go for some licentious old hottie, fwump go their chances of fathering more than a couple of kids before she’s past it.
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Turkana nomads understand global warming

Fergal Keane of the BBC wrote a sad piece about the desiccation of the way of life of the Turkana in northern Kenya. The always dry climate has been suffering years of deepening drought. Decades of lethal corruption have also done their part to make life increasingly impossible. The whole article is well worth reading (and if there was some way to watch his and Darren Conway’s film, Nomads of the Shore, on BBC News24 this weekend, I would), but I wanted to mention one sentence in particular that leapt out at me. Keane is sitting around the campfire after dinner, talking.

They ask me about Iraq: “Why are people fighting?”

Some of them believe the steadily heating climate is being caused by the war.

They have a better grasp of world events than some world leaders I could mention. After all, we wouldn’t have the war if nobody needed oil, and if we didn’t burn oil, we wouldn’t have global warming.

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Dawkins is wrong about God

I’m sorry to be so blunt, but Dawkins’ pronouncements are just plain stupid.

Using religion and God as an excuse to kill people is evil. If he’d said that, I’d agree 100%. Some of the things people do in the name of God really are evil.

But to say that religion is at fault because people make a pig’s breakfast of it is like saying that love is evil because people can use it to hurt each other.

The other thing is, where does he get off, making sweeping statements about God? He’s just finished saying he doesn’t think God exists. If God doesn’t exist for him, he couldn’t know anything about it. I would have thought he was smart enough to see the paradox. (Yes, I do have issues with not separating science and religion. Read more about it here, if you’d like.)

Maybe he should stick to genetics, something he does have a clue about.

Technorati tags: Dawkins, Richard Dawkins, religion, God, evil

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Statistics and the human cost of the war in Iraq

Many commenters on the Lancet study (pdf) boggle at the numbers, point at the uncertainty, express disbelief, and note that they’re not statisticians. Well, I’m here to help.

Although perhaps not very much. I’m not a statistician either. I scraped the bottom of the barrel as a student taking my one required stat class. It was only because Dick Lewontin was a brilliant teacher and exceedingly merciful that I passed at all. But in some ways that may make it easier for me to explain. I know what we all go through when statistics get thrown at us.

I won’t be discussing specifics of the methodology or how they collected data. (For what my opinion is worth, their methodology is excellent.) Billmon, Zeyad, and the Lancet article itself go into that in exhaustive detail. (Update, Oct 19. Another English- rather than statistics-based discussion by Greg Mitchell. Yet one more: Riverbend gives her usual excellent personal take on the numbers.) Iraq Body Count has a much lower number (about 43,000 at the low end of the estimate) because that is a tally purely of deaths reported in various media. Anyone who thinks that the media are cataloguing every single death in Iraq is living in a dreamworld. Of course IBC’s estimate is vastly lower.

I’d like to (try to) explain in a nutshell what the overall numbers in the Lancet article mean.

The main thing that seems to have people’s knickers in a twist is the level of uncertainty surrounding the estimates of the true number of excess deaths. (It’s worth pointing out that the uncertainty would be much lower if the US had lived up to its obligations as an occupier and kept as good a count as it could of deaths in the country.)

There are two different kinds of uncertainty: the uncertainty of not knowing whether your numbers are right because of the difficulty of collecting the data, and the statistical measure of uncertainty. The broad range of estimates, 392979 – 942636, in the Lancet article is due to the difficulty of collecting data. Since getting the data is difficult, the distribution of estimates of the real number of deaths will look like the blue line below. Note that the line does NOT represent numbers of deaths. It represents estimates of what the actual real number is.

(Graphs modified from Wikipedia, showing generic normal distributions to illustrate the concepts discussed. These are not from the Lancet.)

graphs of normal distributions with different standard deviations

The important thing to remember is that the statistics tell you how much chance you have of guessing wrong. The true number has a 68% likelhood of being somewhere in the blue zone in the lower graph above. It has a 95% likelihood of being somewhere within the blue plus beige zones. In the top graph, the 95% zone lies between the dashed lines: as discussed below, that’s a narrow range for the red line, broad for the blue one.

With good data, the chance that your estimate will be far from the true number (i.e. “0”) is low, so the curve is steep and pointy. If, for instance, the true number of excess deaths were 655,000, and the necessary records to count the number of deaths were easily available, the likelihood that the real number of deaths was, say, 600,000 would be vanishingly small. Ninety five percent of the estimates might fall between, for instance, plus or minus 10,000 deaths, as depicted by the dashed lines in the top graph.

With hard-to-collect data, the chance of estimating wrong is much higher. The likelihood that the real number was 600,000 is not vanishingly small. It’s quite large, and 600,000 may, in fact, be the real number. So may 700,000. Both are equally likely. If one wants to stress that the number of excess deaths could be as low as 393,000 according to this study, one has to also stress that it could be as high as 943,000. The uncertainty of the estimate means higher numbers are as likely as lower ones.

What the range of numbers means is that there is high statistical certainty (at least 95% to be precise) that the real number of deaths falls within that range. The range encompasses the blue and the beige areas under the graph (and is represented by the hard-to-see dashed lines at the extreme right and left of the blue line in the top graph). That means there is a 95% probability that the true number of deaths falls somewhere between 392,979 and 942,636. There is a less than one in twenty chance that “only” 350,000 people have died due to the occupation, or that a million people have died. In other words, there is a great deal of statistical certainty that the range is correct. The midpoint of the range is the likeliest true number, but that is less certain.

Hundreds of thousands of people have died. That is not in dispute any more than any other scientific conclusion that rests on a 95% confidence level (i.e. all biological and medical science).

So, now that I’ve cleared that up, can we stop pooh-poohing the numbers and start being appropriately horrified that hundreds of thousands of people have died?

Technorati tags: Iraq, body count, Lancet, war, human cost

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Facts and the danger from GM food

Evidence of harm from genetically modified (GM) food is one of the under-reported issues discussed by the generally excellent Project Censored for 2006. Specifically, they report on studies of rats and mice fed “GM soy” and that the rats died young, were underweight, and/or had other anomalies. There are several things that are missing in almost all the non-technical reporting on GM food (and plenty of things missing from the scientific reports, too).

First, they don’t specify what kind of genetic modification took place. (PC at least does say “Mon863,” but that doesn’t tell us much.) The beans could have been modified with jellyfish genes to make them glow green in the dark. They could have been modified with a vitamin A-producing gene (as some rice actually is). However, they probably weren’t. The majority of GM-ing (about 75%, if I remember right) is done by Monsanto to introduce RoundUp weedkiller resistance into crop plants. Given the “Mon” prefix, that’s probably what these studies were about.

A bit of background is needed here. RoundUp (which, interestingly enough, is made by Monsanto) kills weeds by interfering with their growth hormones. Plants have very different hormones from animals, including humans, and so destroying those hormones shouldn’t have any effect on animals. The problem is that life is infinitely complex, there are vast amounts we don’t know about biomolecular interactions, and chance matches that cause curious downstream consequences are not unheard of. Cannabis, for instance, has an effect on the human brain because a plant molecule (whose probable function is repelling insects) can interact with nerve receptors whose normal target is very different molecules produced by humans.

So, did the rats do poorly because the GM soy had weird stuff in it that was harming them? Or did they do poorly because it just wasn’t very good soy?

Assuming the GM-ing did involve RoundUp resistance, that last question is not rhetorical. The point to the resistance is to allow frequent spraying with the weedkiller without killing the crop itself. (Yes, Monsanto has farmers paying for patented seeds so that they can pay for more Monsanto weedkiller to pour on them.) RoundUp resistant crops are generally also grown with plenty of insecticide spraying and chemical fertilizer, and that kind of produce has fewer vitamins and minerals. That’s a matter of observable fact, but it’s not necessarily anything directly to do with the genetic modification itself. The GM-ing just allows the crop to be produced under even more hostile conditions than ordinary chemical farming.

If the GM soy killed the rats by being the equivalent of a lifetime of soda pop and french fries, then that’s very interesting, but not actually panic-inducing. If it killed them as a direct consequence of the molecules produced by RoundUp resistance, then there really needs to be a red alert. An Australian CSIRO study found an immune response to GM peas (gene unspecified), and that suggests a possible direct molecular interaction. It really, really, really needs follow-up studies immediately. (PC cites this as a “private research institute,” but CSIRO is “the Commonwealth Scientific and Industrial Research Organisation, … Australia’s national science agency and one of the largest and most diverse research agencies in the world.” (From their website.))

The question of why the rats did poorly is absolutely critical, but the point is hardly ever raised in non-technical articles.

Another question I don’t see addressed is not technical in itself, but does require awareness that there are different genetic modifications. Critics of GM food would like to see it banned. Proponents say we have to move with the times or people will starve. Both are being silly. Vitamin A-enriched rice is a Good Thing. Disease resistant crops that require less herbicide or pesticide are also (usually) good. (But consider the impact on Monarch butterflies due to the deaths of caterpillars caused by caterpillar-killing genes added to corn in the US Midwest.) And as for people starving, they aren’t doing it due to a lack of food, even without GM-induced abundance. People are starving because of wars or because staple foods are too expensive. Genetic modification (unless it prevents human greed and stupidity) will do nothing about that.

On the other hand, banning GM food that has no socially redeeming features seems like a good idea. Pouring out more RoundUp is good only for Monsanto. It’s terrible for everyone else. Let us, by all means, ban that.

The point I’m trying to make is that the opposition to GM food needs to be done intelligently. It needs to be based on fact. And a first step in that direction would be for non-technical talk on the subject to tell us what those facts actually are.

Technorati tags: GM food, photovoltaics, frankenfood, genetically modified food, genetic engineering, RoundUp, Monsanto

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Humans still evolving (No. Really?)

From the NYTimes report: [Requires free registration. Or use BugMeNot for Firefox]

“Providing the strongest evidence yet that humans are still evolving, researchers have detected some 700 regions of the human genome where genes appear to have been reshaped by natural selection, a principal force of evolution, within the last 5,000 to 15,000 years.

The genes that show this evolutionary change include some responsible for the senses of taste and smell, digestion, bone structure, skin color and brain function.

Many of these instances of selection may reflect the pressures that came to bear as people abandoned their hunting and gathering way of life for settlement and agriculture, a transition well under way in Europe and East Asia some 5,000 years ago.”

In other news: many trees have green leaves.

I’m sorry, but to me this seems like a “Duh!” moment. Of course humans are still evolving. All Pritchard and company have done is find indications in the DNA that this is so. (These are indications, by the way, and not proof. They are good indications and deserve to be believed, but I expect you will hear people arguing that this isn’t proof.)

The interesting questions are: what kind of selection is happening? Some of it is natural selection, i.e. it has nothing to do with what people admire in mates. Lactose tolerance is probably one of these. People who could benefit from milk survived to reproduce and so their genes for lactose tolerance survived in that population.

Others might be mate selection rather than natural selection. Pritchard and company talk about hair texture genes. It’s hard to see what survival advantage different hair types would bring in a northern climate. (In the tropics, where it can provide an essential insulator, the situation is different.) Hair texture in temperate climates could well be due to the whims of fashion. The important thing to remember here is that sexual selection is notorious for leading to extreme forms that can lead to lower survival rates and even extinction of the whole species. Consider the Irish elk, which developed huge antlers for the purpose of showing off. When the environment changed, and their diet was no longer rich enough to support formation of what was practically an extra skeleton, they ran into big trouble. Sexual selection (and fashion, its young cousin) is an iffy thing.

The other factor is genetic drift. Counterintuitively, random processes can lead to a preponderance of one set of traits. Because of the way reproduction works, once the traits are preponderant, they tend to become even more so. In the end, the minority trait can disappear by random processes alone, without any selection, natural or sexual. Loss of wisdom teeth follows that trajectory. (This is not one of the characteristics the researchers mention.)

The researchers do mention some genes that affect brain development, whose precise function is unknown. The conclusion in the popular press will probably be that these genes must make some people smarter, faster, and better, if not cheaper. Those qualities are so complex, it is highly unlikely that one or a few genes would have much effect on any of them. The brain genes caught in the act of evolving may well do boring things like determine the distribution of glial cells, or affect the blood-brain barrier in subtle ways. They might well be changing by random genetic drift and have no particular significance.

Take all this stuff with many grains of salt. (It tastes better then, too.)

Technorati tags: human evolution, Pritchard

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Solar panel technology takes quantum leap?

Everybody is boggling over the sudden news about a whole new generation of solar panels that have burst upon us from South Africa. So they’re discussed very tentatively (see below). The news first broke in South Africa on February 11, and was reported in Treehugger on Feb 16.

If this is really true, this is the beginning of a new and different world. It’d be nice if we could keep the oil addicts from turning it all gross and greasy, like everything else they touch.

From Pure Energy Systems wiki:

Professor Vivian Alberts of the University of Johannesburg . . . and his team seem to have developed a flexible, thin, metal alloy that is “photo-responsive”. This alloy is said to result in panels with are only 5 micron thick (compared to a human hair at 20 microns, and silicon photovoltaic cells at 350 microns.) Earlier reports (in 2004) indicated the alloy was copper-indium(gallium)-diselenide (CIGS), with another article inferring the panels would have a useful life of about 20 years, with the energy in fabricating them recovered within the first 1-2 years of operation. And that the materials used could all be later recycled to make fresh cells. It is said that a standard family home would need around 30m/sq (“(about the size of a living room”) of CIGS solar panels to meet all its electricity demands.

Unspecified new storage devices (batteries of some sort) and converters have been created alongside these new cells to store the collected energy. It is suggested these new panels can generate electricity even during winter, not requiring direct sunlight to function. Seemingly German investors are behind establishing European plants, which will be producing 1,000 such panels per day, with local South African factories also be contemplated. Much Thanks to TH Tipster Conrad Z. for pointing us to the piece in the ::Cape Argus.

Update, March 20,2006

The “improved solar panels” mystery grows a bit less mysterious. Via Treehugger comments and other sources, the following more detailed info is available.

Eskom (South Africa Electricity Supply Co.) provided some specifics about the panels in June 2005, (information that could, of course, be out of date by now).

Each 60-W panel to be produced is 1,2 m 5 500 mm in size. “The pilot plant has shown the production cost per watt to be €0,95, verified for a 25-MW production facility, assuming a 10% efficiency and average production yield of 85%,” says Alberts.

This means a 60-W panel would cost around R490, or R8 a watt [which equals approx. $1.27 per watt, compared to current technology costing about $5 per watt].

At the moment, intellectual property resides with PT IP Holdco, a company created by the University of Johannesburg.

Arthur Matteson, an electrical engineering graduate student at Michigan State University, noted in comments that the output of the early versions of the panels is similar to current silicon-based panels of similar size, ie 10% rather than 30%. However, cost is noticeably lower.

IFE is the German company that entered into a licensing agreement with PTIP and will be making the panels. (Web site is in German.)

From the company’s press release (pdf) comes the following, possibly rosy, information:

[my translation of small parts of the pdf]

aleo solar GmbH [IFE’s manufacturing subsidiary, I believe] has 16% of market share for silicon-based solar panel manufacture in Germany, and will be making the new panels. It is currently [“Spring 2006” is all it says] building the factory in Brandenburg an der Havel with a 30MW capacity, and expects to start delivering product in mid 2007. In 2009, the company expects to have expanded to a 60 MW capacity.

Eskom in South Africa is also supposed to be producing commercial quantities in the near future. On Eskom’s site, there is also mention of an Australian company producing the panels at some point.

Next year [ie 2006], if all goes according to plan, a full-size plant is to be constructed within South Africa.

This plant will be the first production line of solar panels in Africa. Another plant, in Germany, is set to follow [the Germans seem to be beating them to it], and then possibly yet another, in Australia.

The plan is for any one plant to produce 400,000 60-W panels a year, in order to make up a production capacity of 25 MW per plant.

Technorati tags: solar energy, photovoltaics, Vivian Alberts, energy, oil

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Genetics and Homosexuality

For years I’ve been carrying around an idea about how homosexuality could be inherited. The news reports that jogged me to post are the ones about the work of Mustanski et al. (Human Genetics, online, Jan 12, 2005). The research is currently being widely reported under titles like: Moms’ Genetics Might Help Produce Gay Sons (By Randy Dotinga, Feb 21, 2006) [link no longer active, article removed] [apparent repost without attribution here.]

First a few carps about the reported research, and then some thoughts on my wild(?) ideas.

The Article on genetics and gay sons

Very briefly, this is the gist of Mustanski et al., A genome-wide scan of male sexual orientation (pdf, Jan 2005, Human Genetics). Quoted from the yahoo news article mentioned above:

Women typically inactivate one of their two X chromosomes at random. “It’s like flipping a coin,” Bocklandt [one of the authors] said. “If you look at a woman in any given (bodily) tissue, you’d expect about half of the cells to inactivate one X, and half would inactivate the other.”

“When we looked at women who have gay kids, in those with more than one gay son, we saw a quarter of them inactivate the same X in virtually every cell we checked,” Bocklandt said. “That’s extremely unusual.”

To begin with, what about gay daughters? That wasn’t even part of the study. I’m rather boggled that the researchers expect to say anything meaningful about homosexuality when they ignore one very obvious source of perspective on their findings . (I.e. is the mother’s X-chromosome deactivation as skewed or not when she has gay daughters? In either case, what does that plausibly say about the etiology involved?)

To go on with, how do “gay kids” transform into “gay sons”? The prejudices are showing, and given that the researchers are studying something as ringed with prejudice as homosexuality, that is not reassuring. Also, although the original article shows that the researchers know they are dealing with a possible correlation and not a cause of homosexuality, that’s not stressed enough for the popular press. Note the headline that says Moms’ genetics…”produce” gay sons.

The findings are interesting, but until they reflect a much larger sample size, and more thorough attempt to see what is cause and what is correlation, this is mainly a good start for further research.

The Idea

I was intrigued by the title because I’ve thought for ages that there is an overlooked factor in a constellation of traits which depend on alterations in brain wiring and which are are more common in males than females.

The traits involved are left-handedness (slight excess: about 4:3 male to female), mathematical ability of the kind demonstrated right from the earliest days of childhood, often with associated reduction in verbal ability (I don’t have the statistics handy, but my sense is that this is more common in boys), homosexuality (about 3:2 male to female), and dyslexia (approx 3:1). There are other traits, I’m sure, but those are examples of what I’m talking about.

Hormones play an important role in establishing the “circuitry” of the developing brain, and sex hormones are among the big players. One fact of pregnancy is that the person carrying the fetus is always female. If the fetus is female, her own hormones and those of her mother are more or less in synch, and the brain wiring process is less likely to receive conflicting information even if there is a surge of “strange” hormones. It’s the other way around if the fetus is male.

The placenta is a very effective barrier and generally prevents the passage of huge molecules like maternal sex hormones. However, not all women and fetuses have equally functioning placentas. A “leakier” placenta-uterine interface might, sometimes, let through more of the mother’s sex hormones than usual. With a female fetus, this is less likely to matter. With a male fetus, especially if it comes at a critical time for brain wiring, the surge of female hormones may well alter the process.

It’s important in this context that the placenta is fetal tissue in very close association with specialized maternal tissue on the uterine side. So the genetics of either the fetus or the mother or both could play a role. Clearly, that makes things even more complicated.

The characteristics of the placenta-uterine interface depend on many factors, including nutrition, stress, and so on, but they also depend on genetics. So it may not be homosexuality or mathematical ability, per se, that is heritable. What is heritable may be a placenta or uterus that allows some maternal sex hormones to reach the developing embryo or fetus. This would make the traits in question not inherited, strictly speaking, but congenital. The placental or uterine characteristics are the inherited component.

This does not necessarily mean that, for instance, left-handed people would also tend to be dyslexic. Which trait is manifested depends on individual susceptibility, timing of maternal hormone surges, and exactly which part of the fetal brain is developing right then.

It does mean that any of these charactersitics should cluster in families. In other words, a family with lefties, should also have a higher probability of children with dyslexia, early math ability associated with late verbal ability, and so on. Depending on how big a factor the uterine component is, there might or might not be an association with matrilineal inheritance.

There are several ways to test this idea. Surrogacy, where the egg donor is not the woman carrying the pregnancy, could help to show the relative contribution of each side of the uterus-placenta equation. Genome mapping could identify areas on chromosomes that are associated with more-permeable placenta-uterine interfaces. Then the correlation between those areas and any of the traits in question could be studied. Most directly, if maternal sex hormones could be tagged in some way (not using radioactive elements, obviously) and their possible passage to the fetus tracked, and then if the children could be followed through to adulthood, that would be the most direct way to observe how close the correlation is between stages of brain development, hormonal surges, and subsequent development. The latter research project would be both complex and expensive.

The Big Issues

Whenever the discussion turns to the genetics of homosexuality, a blizzard of issues falls. People imagine future headlines like: “Christian Right Now Favors Abortions . . . In Some Cases.” Ministers who run self-help groups to “cure” homosexuality start to fear a loss of business. Legions of heterosexuals despair when they realize there is no hope for them.

Okay. I’ll admit it. I’m making fun of the whole thing because that, to me, is how ridiculous all the fears are.

Does a genetic component to homosexuality determine whether it’s a choice or a fate? No, not really, because a behavior as complex as sexual orientation is likely to be based on a whole range of causes. In some people it may be a matter of choice, in others it may be cast-iron genetics, and in others it may be anything in between. The genetic or congenital component, as with many complex traits such as intelligence or height, is more of a predisposition than an absolute law.

However, the most important point is that genetics says nothing about how people should live their lives. The most important point is that sexuality is nobody’s business but your own. It doesn’t matter whether it’s a choice or not. The whole debate is useless, because the whole debate is nobody’s business.

Technorati tags: homosexuality, genetics, Human Genetics, Mustanski, Bocklandt, placenta, uterus

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