More Beautiful Women Than Handsome Men

August 4, 2006 3:43 AM

A new study by evolutionary psychologist Satoshi Kanazawa suggests there are more beautiful women than handsome men, finding that attractive people are significantly more likely to have a daughter than a son. Previous Kanazawa research found big and tall parents, scientists, mathematicians, engineers, and violent men tend to have sons; while nurses, social workers and kindergarten teachers tend to have daughters. [Via]
posted by CodeBaloo (57 comments total)

Score! This ratio has my full support.
posted by ®@ at 3:48 AM on August 4, 2006

So what gender would the child of a violent engineering scientist and a kindergarten nurse get?
posted by spazzm at 3:57 AM on August 4, 2006

I think it's obvious that that child would be an hermaphrodite...
posted by Meccabilly at 3:59 AM on August 4, 2006

Hrm. So the consequence of America's lagging in math and sciences is a greater abundance of beautiful women?
posted by Atreides at 4:24 AM on August 4, 2006

i can.. i can live with that.
posted by jimmy at 4:31 AM on August 4, 2006

Which must mean that we scientists and engineers are ugly, ugly people. *cry*
posted by Bletch at 4:31 AM on August 4, 2006

It could be that there are more subsets of the population than attractive people, mathematicians, scientists, and engineers.
posted by Pimonkey at 4:33 AM on August 4, 2006

This can be explained fairly simply:

The theory is this: sperm determines the gender and male sperm swims faster but dies quicker. When the sperm enters the vagina before ovulation, the male sperm will already have run out of steam when the egg finally arrives and the child will be female. Conversely, when the sperm enters after ovulation (the egg is already there), the male sperm arrives first and a boy is born.

Now, beautiful people obviously have sex all the time, so the there is a much bigger chance that there is some long lasting, durable female sperm is waiting when the women ovulates.

Ugly scientists however will only have sex when they are forced to - it is well known that women are hornier when they ovulate; the ideal setting for a male offspring, given the above theory.

Simple, no?
posted by beno at 5:17 AM on August 4, 2006 [1 favorite]

Ugly scientists however will only have sex when they are forced to

Is there some kind of captive breeding program for scientists? That would be a big help in getting them laid.
posted by peeedro at 5:36 AM on August 4, 2006

I have a couple of questions about this study not answered in the article.

1.) The article says good looking parents are 36% more likely to give birth to a girl than less attractive couples. Whereas 56% of babies born to beautiful parents were girls. I'm having trouble reconciling those two statements.

2.) The data set was 2972 young adults. What percentage of these were considered attractive?

Can anyone find a more detailed account of the study?
posted by justkevin at 5:40 AM on August 4, 2006

A theory I heard once that I particularly liked: the survival of a particular gender of sperm is dependent on the hormones of the woman. A very feminine woman, therefore, would have a conducive environment for the female sperm, as well as being more attractive as a female herself (larger breasts, softer curves, etc). This is also not disproved by Kanazawa's data, nor in opposition to his argument.

Which is funny, if true, because everybody thought Henry VIII was an asshole for killing wives that wouldn't bear him a son (as later science would realize the male sperm carries the genetic code determining the sex of the child), but, assuming this theory is true, he would have been right in as much that it was the woman's fault.
posted by GooseOnTheLoose at 5:49 AM on August 4, 2006

JustKevin -- I ultimately linked to Post article because it read better, but noticed the same thing. Other articles I came across said the attractive couples were more likely to have a girl than a boy, not more likely than homely folks to have a girl.
posted by CodeBaloo at 5:54 AM on August 4, 2006

Goose, if Henry VII was right, we was still most certainly as asshole for killing his wives.
posted by BeerGrin at 5:56 AM on August 4, 2006

No, Henry VIII would still be chosing beautiful wives!! But, yes, if Beauty is more valuble to females, a gene which influenced gender of a woman's children based on beauty is likely helping itself (see the selfish gene theory). Likewise, height & violence would be more useful in men.

btw, Its been shown that a women's relationship status slightly influences her offspring's gender, i.e. happy & rich married couples get more boys while single mothers get more girls. And this also happens for the obvious reasons.

Or one might also imagine a positive correlation between ungliness & selective abortions favoring males.
posted by jeffburdges at 6:07 AM on August 4, 2006

This obviously proves that God is either a heterosexual male, a lesbian female, or both.
posted by signal at 6:20 AM on August 4, 2006

Other articles I came across said the attractive couples were more likely to have a girl than a boy, not more likely than homely folks to have a girl.

The 36% more likely statistic seems terribly improbable, regardless of whether it's being applied relative to all couples or ugly couples.

After further reading I noticed that other articles gave wildly different accounts of the study. The Times Online gave the percentage difference as 26% and the number of participants as 20,000. The London School of Economics agreed, but thought the results were being published in the Journal of Theoretical Beauty (which I imagine sells in brown mailing covers).
posted by justkevin at 6:23 AM on August 4, 2006

Evolutionary psychology seems like the field of choice for anyone who enjoys inciting contoversy. Another article by Kanazawa I enjoyed:

Asians Aren't Capable Of Creative Thought*

Miller is correct to point out that East Asians have slightly higher mean IQs than Europeans (Lynn and Vanhanen, 2002). However, East Asians have not been able to make creative use of their intelligence... If Leda Cosmides were born Japanese, she with her high intelligence would have made an excellent product engineer for Sony. But it would have never occurred to her that the human brain might be composed of distinct modules, let alone to modify an obscure logic test to uncover the existence of one such module. That requires massive creativity, which Asians lack.

...Part of Miller's pessimism for the future of evolutionary psychology in the United States concerns its pervasive Christian fundamentalism. Obviously, these people will never understand or accept the theory of evolution by natural and sexual selection... It seems to me that evolutionary psychologists can learn lessons from physicists. Keep them ignorant (the civilians, not the physicists). Let them be taught creationism and "intelligent design" in schools along with evolution. The smart few will realize that there is something wrong with creationism and naturally opt for evolution. They belong with us. Who cares about the rest?

*(With obligatory counterpoint)
posted by Bletch at 6:27 AM on August 4, 2006

We've made a lot of headway in marginalizing the wackos and limiting their power over the last 500 years...

I say we keep making fun of them and showing them up. Nothing says "I'm smarter" than a good old Scopes-style smack down.
posted by ewkpates at 6:31 AM on August 4, 2006

Bletch's post makes me think that evolutionary psychology is like cultural studies, except that it's better at disguising itself as science.
posted by Prospero at 6:41 AM on August 4, 2006

I'm not sure about that prospero, the first article I linked above makes it fairly clear what EvoPsy people think of cultural studies people:

But our enemies are not fundamentalist Christians; they are instead our university colleagues in Women's and Cultural Studies Departments... it is the political correctness in the ivy-covered buildings on our own campuses. The feminists and social constructionists, all of whom have Ph.D.s and no problems with the theory of evolution by natural selection (as long as it is not applied to the human brain), are in a position to do far greater damage to our science than the Christian fundamentalists. Really, what can Christian fundamentalists do to us? Refuse to pump our gas? Spit in our Big Mac? In contrast, our politically correct feminist and social constructionist colleagues control our recruitment, tenure, and promotion processes, and influence our research funding. If anything can interfere with the future of evolutionary psychology in the United States and Europe, it is the cultural insanity of political correctness. That is the true enemy that we must fight.

posted by Bletch at 6:46 AM on August 4, 2006

Before gathering the rope and posse, remember to check context. This letter appears to be a lighthearted, tit-for-tat, point-by-point response to a Miller commentary (an obligatory prepoint?) in which he outline "a 'marketing strategy' [...] that takes advantage of Asia’s relative secularism, freedom from political correctness, sex-positive social attitudes, and intellectual traditions of Hinduism, Buddhism, and Confucianism."
posted by CodeBaloo at 7:21 AM on August 4, 2006

That requires massive creativity, which Asians lack.

Hmm. They were doing pretty well (printing, gunpowder, agriculture etc. etc. etc.) until the Industrial Revolution kicked in. Let's leave it a few hundred more years (with industrial China, Korea and Japan) before we make these kind of sweeping judgements.

I'd accept some cast-iron evidence for creativity genes, but I want to see proteins, hormones, receptor and brain network and structure evidence, not some survey of a few hundred American college students based on what they put on admissions forms, thank-you very much. Same for the sex ratio findings. Human scientists are understandably poor at being objective about humans, so the standard of evidence for evolutionary psychology is much higher than for, say, physics or chemistry.
posted by alasdair at 7:30 AM on August 4, 2006

A crazy guy having an argument with an even crazier guy.

And tall buildings as an indication of cultural vigor? Or maybe that you don't live in an earthquake zone, or in a city that has much older and more beautiful buildings to enjoy. Cause otherwise, Toronto is clearly the centre of the strongest culture in the world.

But Christopher's Wren's St Paul's is more stunning and a greater achievement than any skyscaper. It's even better than the CN Tower.

I do enjoy the irony of a man of Asian heritage making a rather creative argument on how Asians aren't creative. He would probably say that's because he was not raised in Asia, but it's still funny.
posted by jb at 7:34 AM on August 4, 2006

The article Bletch cites seems to be obviously a joke:

Their inability to express themselves in English is likely to hamper Asians' contribution to evolutionary psychology, as long as it remains largely a verbal (i.e. non-mathematical) science, which, for better or worse, it is likely to remain for some time. East Asians might begin to make significant contribution to evolutionary psychology once it attains the level of formalization of the current evolutionary biology. Miller argues that we cannot worry about the accents of our successors, which is true. However, accents are one thing; impenetrably thick accents which prevent mutual intelligibility is another. That's what many Asians have.

If Geoffrey F. Miller were born Chinese, The Mating Mind would have been filled with elegant mathematical equations, and all of his theses would have been mathematically proven. But it would not have been the literary gem that it is, and nobody would have read it. Nobody could have understood him either.

I'm betting that Satoshi Kanazawa isn't Irish and that he doesn't think Asians are incapable of writing in English.
posted by justkevin at 7:38 AM on August 4, 2006

I have a lot of questions. First, the attractiveness measurements. What was the sex ratio of the interviewers? Their race and ethnic background? Age? Were these factors taken into account when looking at the subjective determination of who is beautiful and who is not? Because it is the interviewers who decided who was beautiful and who was not. My personal guess is that male interviewers are far more likely to underrate the beauty of the men involved because of bias towards the women and the general attitude of American men towards gaydom.

Second, our society places a greater emphasis on female beauty and male accomplishment. So does this particular study go for the entire world? Since the sample was all U.S. born children, I wonder how far this particular "trend" can be reproduced in other studies.

I always have huge problems when I see subjective measurements like "beauty" or attractiveness coupled to genetics, which is much more quantifiable. Far too many opportunities for bias creep into these studies than is regularly acknowledged by their proponents.
posted by Ironmouth at 7:57 AM on August 4, 2006

So the consequence of America's lagging in math and sciences is a greater abundance of beautiful women?



I have a plan, mein Führer!
posted by Blazecock Pileon at 8:12 AM on August 4, 2006 [1 favorite]

Bletch's post makes me think that evolutionary psychology is like cultural studies, except that it's better at disguising itself as science.

Its much worse, because it pretends to be a science. I haven't seen or heard of a single evolutionary psychology study that hasn't been more than a "just-so" story, based on dubious statistics and demonstrably wrong assumptions about human evolution.

I want to see proteins, hormones, receptor and brain netwo

Absolutely agree, though I should point out that the standard of evidence for getting published in evolutionary psychology is a low, low bar to stumble across.

I always have huge problems when I see subjective measurements like "beauty" or attractiveness coupled to genetics

Right. Is the standard for beauty the same here as in Africa? As five hundred years ago? As during the Pleistocene epoch?
posted by bumpkin at 8:18 AM on August 4, 2006

Crap. The second quote should be Alasdair's

I'd accept some cast-iron evidence for creativity genes, but I want to see proteins, hormones, receptor and brain network and structure evidence, not some survey of a few hundred American college students based on what they put on admissions forms, thank-you very much. Same for the sex ratio findings. Human scientists are understandably poor at being objective about humans, so the standard of evidence for evolutionary psychology is much higher than for, say, physics or chemistry.

Looked fine on preview. Who knows ? Maybe I haven't the genes for posting on Metafilter.
posted by bumpkin at 8:20 AM on August 4, 2006

As someone with a degree in evolution, I have to say that I completely and utterly hate evolutionary psychology. These kinds of controversial speculations invite the idea that evolution is some fantasy-science where you can just imagine reasons for things.
posted by unknowncommand at 8:31 AM on August 4, 2006

Anyone else think this is total bullshit? Of course the Post article only mentions the universally-accepted hotness of Tom, Katie, Brad and Angelina.

Maybe they used hotornot.com...
posted by hoborg at 8:32 AM on August 4, 2006

Yeah, but once you go Pleistocene...uh....oh, man...
*drinks coffee*
Once you go Pleistocene you never Gomphotheriidae.
(I’m the Torquemada of puns)
posted by Smedleyman at 8:35 AM on August 4, 2006

i'm going to have another cup of coffee to make sure i understand what's being said in these articles, but on initial skim:

w. t. FUCK?
posted by ronv at 8:54 AM on August 4, 2006

Once you go Pleistocene you never Gomphotheriidae.

You're so having a boy.
posted by fusinski at 8:58 AM on August 4, 2006

I think evolutionary psychology is utter garbage. (I love (I mean hate) the ones who talk about how when we were all cave people it made sense for men to be like such and women to be like such, which shows why we now should all follow "the rules" or some crap.)

But speaking of scientists/mathematicians/engineers versus nurses/social workers/kindergarten teachers ... My world of public interest law is filled with women, sort of like the social worker world. The lesbian women tend to do fine, but the straight women are often single. (The "regular" male lawyers are usually our opposing counsel, married, and generally, well, no.) So I have this idea that we should establish a sister profession sort of like a sister city, with some predominantly male occupation like carpentry or engineering.
posted by ClaudiaCenter at 9:02 AM on August 4, 2006

"As part of the study, the interviewer rated the respondent's physical attractiveness on a five-point scale that ranged from "very unattractive" to "very attractive."

They had a single data point on attractiveness? HOT or NOT is more scientific.

...

Question 42: Does the respondent have cooties?

Question 43: How "l337" is the respondent?

Question 43: Do you think the respondent is "all that?"

Question 44: And a "bag of chips?"

...
posted by elderling at 9:02 AM on August 4, 2006

I wonder if this explains why so many fat balding men are with beautiful slender women.

Or is it the Mercedes SL500 in the driveway.
posted by The Jesse Helms at 9:06 AM on August 4, 2006

Things that make ya go "Hmmm"? When I saw the title and lead sentence of the original blog post, I thought that it is common to see a gorgeous woman with a butt-ugly guy, but how often, really, do you see a gorgeous guy with a butt-ugly woman?
posted by CodeBaloo at 9:21 AM on August 4, 2006

Not much was happening until I whipped out my tools at the public interest law offices.
*buh bu bum ba da dee dah*
...did somebody call for a probabilistic structural reliability modeling simulation of stochastic environmental loads?
*buh bu bum ba da dee dah*
...and a bag of chips?

My wife is very attractive. I’m very violent. So, what, we’re going to have either a beautiful man or an amazon?
posted by Smedleyman at 9:23 AM on August 4, 2006

You forgot the batshitinsane tag.
posted by prostyle at 9:25 AM on August 4, 2006

To be honest, I don't see what's particularly objectionable about the study. It wouldn't surprise me at all to find that attractive parents (or, more specifically, attractive mothers) are statistically more likely to have daughters. Physical attractiveness is far more important for females than for males, and to the extent that beauty correlates with fertility -- which it does, strongly, across cultures and time -- there's an obvious mechanism for connecting physical beauty with the gender-determining chemistry of the womb.

The only science-related question I'd like to see answered is the connection between attractive parents and attractive children. While I'm sure there is one, I highly doubt it's as clear as the article assumes. In particular, I'd wonder whether attractiveness in women is more heavily determined by genetics than it is in men.

The crap part, as is usually the case with evolutionary psychology, is ridiculous overreach when connecting this data back with society. The instances of celebrity offspring, for instance, are like using this morning's weather as evidence for global warming. And the "conclusion" that there are more attractive women than men seems to be about four steps removed from any sort of statistical support.

The thing is, I can see all of that crap entering the story from the offices of the Washington Post, rather than from the paper itself. Maybe the scientist is a hack (and others have certainly cited evidence for it) but I tend to feel that evolutionary psychology suffers from crappy populizers more than anything else.
posted by bjrubble at 10:29 AM on August 4, 2006

Please stop using the word "attractive" as if it were some sort of objectively determined universal constant.

In very recent history, certain types of people have made oodles of money off of their specific kind of beauty, and they have invested a hefty percentage of those oodles in making sure their type of beauty is regarded as "Beauty." We'd do well to remember that.

Angelina Jolie is hot. Not gonna lie. But nearly every other model and celeb "hottie" that gets trotted out gives me the yawns. Seriously. These people are plain. Oh look! Another skinny blonde with big tits and pouty lips and curly locks and high cheekbones and THE SAME VAPID COUNTENANCE ALL THE OTHERS BEFORE HER HAD. This is beauty? When did predictability become beauty? When did conformity become beauty? And when did this particular American affliction become the standard for everywhere else?

That "study" is flawed from the start.
posted by poweredbybeard at 10:41 AM on August 4, 2006

Another skinny blonde with big tits and pouty lips and curly locks and high cheekbones and THE SAME VAPID COUNTENANCE ALL THE OTHERS BEFORE HER HAD. This is beauty?

It's all plastic surgery. Really fucks up natural selection, no?
posted by The Jesse Helms at 11:00 AM on August 4, 2006

I guess Dr. Strangelove had the right idea. A few military men deep underground prodigiously breeding a large pool of beautiful women of a highly stimulating nature. It would certainly bring a good balance of systemizing minds and empathizing minds. But it is, you know, a sacrifice required for the future of the human race...
posted by rolypolyman at 11:07 AM on August 4, 2006

... and what poweredbybeard said. What passes for beauty right now generally sucks ass.
posted by rolypolyman at 11:09 AM on August 4, 2006 [1 favorite]

I have a couple of questions about this study not answered in the article.

1.) The article says good looking parents are 36% more likely to give birth to a girl than less attractive couples. Whereas 56% of babies born to beautiful parents were girls. I'm having trouble reconciling those two statements.

56% girls means 6 % more likely to have a girl than a boy, so therefore the good looking parents are only 30% more likely to give birth to a boy than less attractive couples.

They dont seem to have considered the possibility that the stress of parenting boys will make you less attractive!
posted by Lanark at 11:10 AM on August 4, 2006

Correct me if I'm wrong here, but I think I know why the women were so much more likely to be rated as "attractive" than the men.

Throughout social history, the attractiveness of women has been more important for pairing than the attractiveness of men, because women had little if any choice in the matter for so long. This doesn't mean that there weren't attractive men, of course, just that it didn't figure into the equation. As women were given choice in the matter much more recently (at least in Western culture) there is much less common consensus on a male standard of beauty than on a female one.

One male subject might be seen as very attractive to one interviewer, and repellent to another, thus shifting the data more towards the center. This effect is less likely with women, where the data will be VERY strongly correlated with weight, breast-size, etc. Also, men are mentally trained to look for women to be attractive, I think, which probably skews the survey even further.

I think beno has it right. Attractive people have more sex, x-chromosone sperm outlast y-chromosone sperm and will be there waiting during ovulation.

I wish I could find the recent post about Blond hair being an evolutionary anomoly propogated by making the Blondes more attractive to potential mates. It just cracks me up watching how many guys still snap their brains into the blonde=hott! formula when out at the bars.

Maybe I just enjoy have tastes in women that go contrary to the frat guys.
posted by Navelgazer at 11:40 AM on August 4, 2006

Evolutionary psychology is just intelligent design backwards.
posted by srboisvert at 12:02 PM on August 4, 2006 [1 favorite]

Argh, I hate this shite. It gives a bad name to real science. When will it just go away?

Let's see... I have a son. Does that mean that I was hot, or not?

Attractive people have more sex

Yeah, right. Oy.
posted by jokeefe at 12:52 PM on August 4, 2006

Whatever the case we can congratulate ourselves as coming not only from a long, long, long series of male orgasms, but also having ancestors who were fit enough to reproduce before they died and out reproduce everyone else, so take that Neanderthals!
posted by Smedleyman at 1:46 PM on August 4, 2006

Some other articles reporting on the study gave a little more detail about the beauty assessment.

Scotsman:
Dr Kanazawa based his conclusions on data from 3,000 Americans, who were assessed for factors that provide an objective measurement of attractiveness, such as symmetry, and characteristics, such as female breasts or male body hair.

The Courier-Mail:
People from all societies agree on who is beautiful and who is ugly, he stressed.

Statesman:
Asked whether rankings were subjective, Kanazawa argued that physical attractiveness is an objective quantitative measure, just like height and weight.

"Standards of beauty are both innate and culturally universal, and everybody agrees on who is beautiful and who is ugly just like they agree on who is tall and who is short," he said. The top factor is facial features, he said.

He said computer programs can precisely measure someone's physical attractiveness.

Um...color me skeptical.
posted by Pryde at 3:18 PM on August 4, 2006

Evolutionary psychology is a science. You make falsifiable predictions & run experiments. Scientists are human & occasionally nuts. But unlike "social scientists" real scientist make a (small) prediction, test it, & declare (small) progress. btw, I've never seen evolutionary psychology make a grandiose assertion, always some little claim about gender ratio, mating strrategies, etc.

Most who study evolutionary psychology have exactly the same social goals as those who bitch about evolutionary psychology, i.e. gender equality, etc. But evolutionary psychology tries to provide more successful methods by understanding our limits.

btw, Mathematicians or physicists are quite happy when shown that one method may not work. But social scientist are quite threatened. But education research has the same problem as social science. One big ass dorm room bull session spending grant money on bullshit, until some simple experement shatters some basic feel good assumption.

However, the particular data set used here is apparently not very good. Doesn't mean the experement is garbage, still a cute idea. But it wont be taken seriously until its been corroborated with much better data.
posted by jeffburdges at 5:20 PM on August 4, 2006

1.) The article says good looking parents are 36% more likely to give birth to a girl than less attractive couples. Whereas 56% of babies born to beautiful parents were girls. I'm having trouble reconciling those two statements.

Try taking the percentages out of the statements, and you'll see that they have no bearing on the truthiness of one another:

"good looking parents are more likely to give birth to a girl than less attractive couples"

"a majority of babies born to beautiful parents are girls"

The two statements are talking about two different sets of data. The first one is the number of girls born to attractive parents compared to less attractive couples, and the second one is the number of girls born to attractive couples compared to the number of boys. They neither support nor contradict each other.
posted by oneirodynia at 7:16 PM on August 4, 2006

Ugh. Crap science with sexy headlines.

Instead, let's do a study on who is more likely to get facial plastic surgery, pretty people or not-so-pretty people. (I betcha it's the former.)
posted by desuetude at 8:09 PM on August 4, 2006

1.) The article says good looking parents are 36% more likely to give birth to a girl than less attractive couples. Whereas 56% of babies born to beautiful parents were girls. I'm having trouble reconciling those two statements.

(Even though it's already been responded to:)
56% of beautiful parents had girls.
41% of non-beautiful parents had girls.
At least, that's how I'd interpret it. 56 is 36% larger than 41. That 36% is so ambiguous it could mean all sorts of numbers instead of 41, but they're implying it's smaller, anyway.

Physical attractiveness is far more important for females than for males, and to the extent that beauty correlates with fertility -- which it does, strongly, across cultures and time -- there's an obvious mechanism for connecting physical beauty with the gender-determining chemistry of the womb.

Okay, I originally had a big response to this, but then I read the quotes Pryde provided. It really would hold more water for me if this was, as was assumed by some previous commenters, attractiveness rated in snap yes/no decisions by a sample of the population. That, I think, would be much more true to the instinctual urges that we could infer from this study.

If a large sample of people finds someone attractive, then there is no disputing the fact that they are attractive, for a definition equal to 'attracts people', and there's no reason for us to develop a (biological) urge to have sex with people who are (biologically) wastes of time, i.e., infertile.

Even though the attractiveness of the subjects was rated by analysis rather than subjective survey, it's probably not that far off. I do find that symmetry has a lot to do with it, and facial characteristics. Remember that we're talking about large-scale attractiveness, not what you think is pretty. You Are Never A Representative Sample.
posted by blacklite at 11:24 PM on August 4, 2006

"Standards of beauty are both innate and culturally universal, and everybody agrees on who is beautiful and who is ugly just like they agree on who is tall and who is short," he said.

Whaaa? I've never heard such a load of bullshit in my life. Sure, maybe you'd get more of a consensus within one society or culture but you only need to go to another country to see that views on beauty vary widely. Widely.
posted by liquorice at 5:14 AM on August 5, 2006

I'm pretty skeptical about this. A few things strike me.

1.Can't remember if it was Dawkins or Gould, but one of them mentioned the elephant seal paradox. Elephant seals are highly polygamous, with one male servicing a large harem of females. So, you might expect the sex ratio of new-born elephant seals to be skewed. In fact, it's almost exactly even. The reason: every individual has exactly one male parent and exactly one female parent. Whatever the mating odds, there is a very powerful evolutionary pressure to keep the sex ratio even. How come this weak-looking beauty pressure can overcome that?

2. Kin selection. Human beings don't congregate at random: they tend to live in tribes or villages where a large proportion of people have some kind of family relation to them. If you have these genes for producing mostly-male or mostly-female children floating around, that's going to be a problem for their owners: you're going to be surrounded by people of your own sex.

3. The biological mechanisms to allow this seem complicated and detectable. Since the overall sex ratio is almost even, if there are produce-daughters genes there must also be produce-sons genes. Produce-sons will be most often found in men, produce-daughters in women. Therefore either the sperm or the ovum/womb must be able to influence sex ratios. According to this, sperm are either X or Y sperm, that will produce male or female embryos.

So if Kanazawa is correct and ugly men, or scientists and engineers are more likely to have boys, it should be pretty easy to detect experimentally. Take sperm samples, and see if there are more Y-sperm in there. Similarly, if a female can reject a certain kind of sperm, or selectively reject male fetuses, there ought to be some detectable mechanism for it.

Fertility and infertility seems to be a pretty big, well-researched area of medicine. If the theory is true, it seems odd to me that no-one's noticed these biological effects.
posted by TheophileEscargot at 7:00 AM on August 5, 2006

TheophileEscargot,

1a) We are talking about very small changes in the ratio here, i.e. the ratio will remain "nearly" even. Dawkins quotes research saying the Elephant seal ratios are "nearly" even.

1b) Most male elephant seals may never have any kids. But this just means the pay off for being a successful male is *much* higher.

2 & 3) Ain't nothing wrong with having millions of "produce more daughters" and "produce more sons" genes fighting it out. But we're talking here about a few genes who "got smarter" by being conditional on other factors.

btw, See kangaroos if you want an interesting species.
posted by jeffburdges at 7:01 AM on August 7, 2006