where the boys are
I don’t know if anyone else has heard this report, previously made and today vociferously defended on NPR and perhaps circulating elsewhere, about single moms producing fewer boys than partnered ones.
It seems a boffo exemplar of contemporary kinship anxiety.
The reported facts are as follows:
(1) Boys have always been born in slightly higher numbers than have girls
(2) Boy-baby pregnancies require a slightly higher energy investment on the part of the mother than do girl-baby pregnancies
(3) Recently, the boy/girl discrepancy has been dropping. There are still more boys born than girls, but not as many more
(4) Single moms contribute to this decline in the discrepancy — they are (supposedly) statistically less likely to have boys than are partnered moms.
The currently-circulating explanation is: somehow, humans are rapidly adapting to family instability; women’s bodies can “tell” if they haven’t got a male partner around to help out, they know it’s a big effort to produce a boy baby, and so they refuse to take any chances about male fetuses (or blastocysts, or implantation, or maybe even ovule friendliness toward Y chromosome sperm — the explanation part gets a bit hand-wavey here). To summarize: the bodies of single women are mysteriously inhospitable to male offspring.
The pop-cultural demographic take-home message, but of course, is: get out your tinfoil hats and await the parthenogenetic lesbian apocalypse.
But before we measure our heads for good fit, we might note that there is a gigantic black box in this explanation, capaciously enclosing the whole “how” part of the problem.
If all we need is an explanation that fits the available facts, with mystery clauses thrown in as necessary, I’ve got one, too — but I bet it won’t make the news.
It’s hard to see how energetics would operate any kind of constraining force, given that malnutrition is far less a problem for we moderns than it was for our ancestors. So let’s set the energetics aside. Although boy babies are energetically more difficult to carry to term than girl babies, they must be easier to successfully gestate in some other important ways — otherwise how to explain the ratio of boys to girls at birth, given the objectively 50/50 odds of conception? Working from this premise, one may as easily conclude (since we are unburdened by the need to offer any “how” account) that there is a positive rather than a negative message being received (mysteriously, of course) by single women’s bodies: “psst, you are in a position such that it is worth trying to bring off the rare girl rather than the more usual boy.”
Does this sound like a crackpot theory to you? Keep in mind it has as much to recommend it as does the reverse proposition, merely flipping the evaluative language.
The decline in boy babies *is* disturbing because of what it probably indicates about environmental contaminants. As for the single-mom part of the story, well — I can’t tell you *why* it is wrong, but I’ll happily offer a wager of $50 to the first taker that if will be thoroughly debunked within 5 years and probably much sooner. Unless that counts as internet gambling and could get _Savage Minds_ in trouble, in which case I will satisfy myself with shaking my fist and intoning, Mark My Words. ;)
Now this might all be hokum but back half a dozen years ago when discussing the sex of our as of yet unborn child with the midwife she explained a natural “rhythm” method of gender selection. This was based on two “facts” that I am not qualified to evaluate: male spermatozoa are faster swimmers and they are also not as hardy and do not live as long. We did not care about the gender of any of our kids so I must admit that we did not do our part to test her underlying method.
If this is in fact true, then I can see lots of differences in behavior that one would assume goes along with being single or married that must be controlled for first. How do the rates for cohabiting females compare for instance? It would not take much of a common pattern to show up as a statistically significant blip.
It just sounded a bit like the assertions was being made that there could not be a plausible explanation and that this was all media paranoia. Then again I don’t know anything about the original source so that may well be the case.
Does anyone have a link to these studies? Or the defenses of them?
Vitpil — actually, I don’t. I read somewhere that this study is published in New Scientist, but I don’t have the link. It may be traceable via NPR’s website.
Lurk — I had to do a bit of parsing of your message to catch your meaning, so I may be misreading. I assume the “rates” to which you refer are a bashful reference to how often partnered vs. single women have sex. So — let’s say your midwife was correct; that Y sperm are fast yet fragile so sperm that have survived several days of no sex before ovulation are more likely to be X sperm; with frequent sex, on the other hand, that it is likely that fresh sperm will be present on the day of ovulation and that the speedy little Ys will beat out the more lethargic Xs. And let’s further assume that partnered women in the aggregate have sex more often than single women in the aggregate. If all of this is true, sure, we could see fewer boys from single moms as a result.
But the point is that this eminently falsifiable hypothesis is VERY different from the explanation proffered by the yes, paranoid and yes, media-promulgated account that I described. I never said there was *no* reason fewer boys are being born — there has to be a reason. What I was suggesting, instead, was that the account presented in the NPR report was nonsensical, and that it could only strike otherwise-reasonable people as probable because it confirms their suspicions about the decline and fall of civilization as we know it.
Sorry for not writing in a more direct manner, it was not the subject at hand I was skirting but rather the wrath of the locals. I have to admit that I am a bit weary writing on this board after seeing the way the anthropological community here went after the physicists and some of the poor souls in the evolutionary psychology thread. (Who by my reading only were arguing that evolutionary pressures must have had some effect on psychology, they were not advancing or even aware of the specific theory of the same name.) Needles to say I was trying to avoid going out on a limb with statements I cannot authoritatively defend.
So with the caveat that this is all based on random PBS documentaries, paying attention in “so yer gonna have a baby class” and my freshman biology course twenty years ago lets try again.
The mechanical explanation you gave is the one I had in mind for the basis for how to naturally select the sex of your child. The difference in sperm motility was something we covered in high school biology and was presented as an explanation of the 52%-48% split in the rate of male to female births. That is also something that I have seen in many other contexts so your assertion that there should be a 50-50 split struck me a incorrect.
The reason that I used the midwife example was to suggest that there are very real behavioral inputs to the sex of the child. Furthermore, my mention of “rates” was a ham handed attempt at suggesting that there might be even more going on on the pre-conception side of the equation. The specific study I had in mind showed that there was a tendency among women who were married but not monogamous to prefer sex with their husbands where they were less fertile and with there external partners when they were more fertile. [I think that this one was on the Discovery channel ;-)] If this tendency is present then I would be very surprised if it did not manifest itself in the behavior of single women in some way. In conjunction with the above differences in the sperm population over time it just makes sense that there would be some difference even without trying to figure out what it specifically is. Finally, single sex and married sex are different, for better or worse — again we would not be surprised by some difference in the final outcomes.
So given all that my reaction to the basic data you mention is really more “Well, Duh.” than anything else.
The posited explanation itself is actually kind of interesting and eminently testable, once the other conditions can be controlled for. I don’t suppose that such a study would get past an IRB board though so I suspect that it would have to be tested indirectly. One good candidate might be lesbian couples who have children in vitro, that would remove the male partner from the equation. Another thing would be to look at very early miscarriages to check for instances where the mother was “rejecting” the high cost male child.
Personally, I agree with you that the idea that this is a response to resource availability is totally off base. My logic is that any child is so expensive that the minor difference between a male and female child is way down in the noise. If it is too risky to have one it would certainly be too risky to have the other.
That said I think that your theory that there is an ominous environmental cause at work is just as bad of a reaction as the tinfoil hat theory you are critiquing. It seems as though it is presented as the real “root cause” to dismiss out of hand any theory that might indicate that the actions or biology of single mothers could actually be responsible – that such theories are morally repugnant and not worthy of consideration.
Well that was a bit more confrontational that I wanted, but hey I missed my mark the other way on the first try. I’ll get it right after a while.
hmm, I must have missed the physicist discussion but I know I did indeed direct some wrath at evolutionary psychologists and would happily do so again should the opportunity arise :)
The possible environmental cause for the decine in male babies is not actually of the tinfoil hat variety; it is well-established that many synthetic chemicals mimic female sex hormones and/or interfere with androgens. But even if this is a causal factor, one would anticipate it would influence single and partnered moms equally.
In my previous post, I agreed that indeed, were it true that single moms have sex less often than partnered moms, one might see (for the reasons discussed there) an increased incidence of male babies from partnered women. Note, though, that this is actually a behavioral cause — not a difference locatable within single vs. partnered women’s bodies per se.
The report which I critiqued was arguing for some mystery mechanism, LOCATED IN SINGLE WOMEN’S BODIES, that responded to the external cue “no man, no resources, don’t have a boy”. The report offered no plausible such mechanism. It just posited one. So in my post, I pointed out that this was silly and unpersuasive, and only received national media attention because it matched popular prejudices.
What I was doing was applying my critical faculties to something I heard and examining it for plausibility. Also known, I guess, as the “wrath of the locals”.
The Discovery study to which you referred prompts a very similar reaction — my first question is, what kind of sample size of “married not monogamous totally willing to have ovulation tracked by, and report any and all sexual activity to, researchers” women was used for this study? From this rather tenuous report, you go on to postulate some further (unspecified) behavioral implication for single women. Dude, totally okay by me; speculation is an important part of serious thought. But don’t proffer it in the guise of persuasive argument and expect not to be called on it.
As for testability — yes, yes, right on. I was trying to point out that the hypothesis suggested in the original report was so underspecified as to be utterly untestable, therefore not falsifiable, therefore not verifiable; such that I was prompted to wonder: hmm, what’s going on here? Why is this being treated seriously? And I suggested a reason why. I also suggested a test for my reason — would the equally (im)plausible alternative receive national attention? No. why not? etc. (I don’t want to repeat my original post).
I do think it is important, when one hears “scientific” reports, to think about them critically. And in doing so, to think about how research actually gets done. The partnered vs. unpartnered lesbian study you suggest — this would actually be a test of the original premise, though would offer so many other kinds of external factors (a result disproving the original thesis would be subject to new challenges: how can we know if _men_ but not women give off “provider” hormones to their partners? etc?) that again, it seems clear that what was being offered in the original report was an absolutely untestable pop theory dressed up as science. As for your second suggestion, collecting and testing early miscarriages — *very* early miscarriages are not detectable, and later ones aren’t necessarily something legions of study subjects would want to keep frozen in baggies till they could get them to the lab. Sorry to be gross, but really, *think* about how research results get generated and what is knowable and what isn’t. Considering what one hears in this way is, inherently, a confrontational process. but if you get anything from Savage Minds, I hope it is a sense that it is always worth it to jump into that process!
Just to fill in some gaps and keep playing devil’s advocate. ;-)
Rage against the evolutionary psychologists, it is a nobel task. The thing I was commenting on was the collateral damage, there were a number of people who I felt got taken to task for being evolutionary psychologists who weren’t. It was like in a meeting or lecture and someone asks a question and the speaker goes off or some totally incorrect interpretation. One just feels sorry for everyone involved.
Not coming from the anthropology community I was actually struck by how many of the anti evolutionary psychologist arguments sounded just like the anti-evolution arguments one hears from the Discovery Institute or the like. Once the precise definition of “evolutionary psychology” was made clear, it was evident that there were two camps arguing in different terms. But there were long passages where I felt embarrassed for both groups as they talked past each other. Now I came to that thread after it was cold and I think most of those things were resolved by the end, so I did not pipe up myself.
I certainly agree that the assertion in the report you mention is a bit questionable. I have also had first hand knowledge of scientific results in the news and I must say I winced to hear how the reporters butchered the results. So my first reaction is usually to assume that the science was sound but the layman-ification of it went awry. So, I am left wondering was this bad science or bad reporting. I still think that the energy differences are insignificant compared to the total cost of the child and I have a hard time believing that they would provide enough of a benefit to be actively selected for.
I am not opposed to the idea that there is something in the bodies of single moms that might drive this effect (if it really exists). Although I would expect it to be part of a secondary effect to some other mechanism. Digging into my bag of reproductive folk wisdom, we had a good midwife I tell ya. One of her suggestions was that regular sex prior to conception helped accustom the mother’s immune system in such a way that miscarriage was less likely. [In retrospect her prescription for almost everything was to have more sex :-)] Now if this is true then it would be plausible that this effect could be more protective of male children than female children. Now this is all just pie in the sky speculation but if there is some truth in the folk wisdom I have received on this subject then such an internal to the mother mechanism would not be outside consideration. That said, I don’t think that it would be the primary reason for whatever mechanism would be uncovered.
I agree that environmental factors are important, and you mentioned why I thought they were not an appropriate cause in this case. There is no reason to think that single and partnered parents have different exposures. Also not only are there artificial sources out there, soy is chock full of estrogen goodness, IIRC.
The Discovery report (if it was Discovery I am not 100% certain) was based or research done on some non-western society where women are permitted to have sexual relations outside of the marriage. I am sure that they did not elaborate to much but as I recall they interviewed the women in the group and recorded when they had sex within/outside of the marriage and when they menstruated. There was not a direct measure of ovulation but rather the standard count umpteen days from the start of your period thing. Now I am suspicious of any polyamorous-gee-arn’t-us-westerners-so-repressed studies in general since they do not pan out that often under a second examination. This one struck me as being reasonable at the time, it was kind of boring and not really presented with an obvious agenda. It is not a perfect study but I don’t think that you could ever concoct such a beast, I agree the one you suggested as impossible certainly is.
Sorry to keep jumping around on my reply. I didn’t make an outline and I keep scrolling up to see what I still need to address ;-) On my offering speculation as serious argument that is not my intention. I was arguing against the position that such an explanation could not exist, so in a manner of sorts my speculation in presented as a kind of existence proof that these sorts of ideas should not be dismissed out of hand.
As to the discussion about the practicality and appropriateness of the experiments that could be conducted I fully understand. I also would argue that in many cases the results might not be terribly valuable. For instance if this effect we are discussing is actually the one originally described it really is not terribly interesting in and of itself. The really interesting thing to look into would be why does this effect happen. What is the mechanism driving this difference? Once a mechanism is posited it may well be possible to indirectly evaluate the original question. For instance, a I’m-too-stressed-without-a-man-to-carry-a-boy marker might be detected or suppressed and the effects on the resulting birth rate evaluated.
I take it as a given that the primary effect you are interested in evaluating may not be something you can really measure. But then one needs to come up with a creative way to get at it through some other means. In the end any experiment is only useful if it can give us some insight into the why of what is going on. If I prove that left handed brunets are better drivers, so what. It it interesting but not really interesting until it fits into a greater whole that tells us something about the real why.
I think that we are actually in agreement on almost everything. So how do you think evolution has influenced our psychology? ;-)
I’ll take agreement where I can find it, so am happy to table the previous discussion! the query about evolution and psychology — well, at risk of taking seriously a question you perhaps meant as a joke…. don’t groan, but I *do* have some thoughts on that too! (you had to have been aware you ran this risk)
My short answer is that of course there must be some influence, but that I can’t imagine how we could isolate it from everything else that influences our psychology.
My long answer I’ll offer in the form of a parable (sorry, more shades of the Discovery Institute and creationism…).
Let’s say you go to a housewarming party at some friends’ swanky new tract mansion way out in the suburbs — they are delighted to have been able to afford so much space, though at the cost of a long commute. No public transportation is available in such neighborhoods, so you have to drive. At the party, morose about your own virtuous yet tiny urban apartment, you get drunk, such that you have to spend the night passed out on the floor of their new home theater/ media room. Around 4 am you wake up having to pee, stagger around the unfamiliar and ginormous edifice looking for a bathroom, and, lost during the journey, you smack headfirst into a doorjamb. The next day you appear at work with a giant shiner. Naturally enough, people ask you what happened. Let’s say you answer either:
1) “goddamned urban sprawl”
or
2) “smacked my face into a hard surface”
Both answers are, strictly speaking, true; but few people are going to be satisfied with either: the first because it is way too distal a cause (sure, were it not for urban sprawl, the whole series of events would not have been set in motion) and the second because it is way too proximal (the face-smacking is the very very end of the story).
Why would you proffer such explanations? Probably because you’d really, really, really rather not talk about the middle part.
That, to me, is what evolutionary psychology does — it connects the MOST INCREDIBLY IMMEDIATE PROXIMAL phenomena (mostly psychological — why people buy stock, why they obsessively google their high school exes, why they enjoy video games) to the MOST INCREDIBLY DISTAL causes (namely, evolution). That way, they get to skip the usually much more relevant, much more explanatory, and much more discomfiting “middle parts” — which include developmental biology, environmental factors, socialization, culture (including language), and, yes, sexism racism class power and the all-important category of flotsam and jetsam.
Or, to put it in the words of the master regarding ev psych’s antecedent, sociobiology, it offers “a kind of bargain made with reality in which an understanding of the phenomenon is gained at the cost of everything we know about it”. (Marshall Sahlins, _The Use and Abuse of Biology_ 1976: 15)
whew. back to actually writing actual articles about my actual research…
I for one welcome our new lesbian overlords.
Angling for the Minister of Culture post, I see…..
Any idea about the original sources?
If they looked at single mothers and their children living at home, it could be biased by things like single mothers putting male children up for adoption more often than female children.
Very poor research, but good enough for the media.