Basically, it says that meat-eating moms are 20% more likely to give birth to boys then vegetarian moms. As a vegetarian who would potentially like some variety in the future potential LittleRiddles, this troubles me. The sperm determines the sex, so what would the mother’s dietary habits have to do with anything? Could it be that the same amount of boys are conceived, but the vegetarian mothers bring fewer boys to full term? Any vegetarian Dopers out there who care to share the gender of their children?
While I can’t really comment on the study, I think a comment on the following line in your post might help allay some confusion:
While the sperm does determine the sex, the utero environment plays quite a part as well, in at least two ways:
The level of acid in the vagina/uterus plays some level in determining which sperm survive and end up fertilizing the eggg.
Even after conception, while the X or Y chromosome from the sperm is a major factor in determining the child’s sex, this genetic predisposition can be overridden in early stages of fetal developpment by severe hormonal imbalances in the mother.
I’d wager that the study refers to one of these factors, and, assuming I’m right, I’d go double-or-nothing that it’s the first (since XY women and XX men are extremely rare, though they do exist).
So the sample size in this case—250 women—wasn’t considered big enough for “statistically significant” results, but a sample size of about 400 was? Hmmm. I’d like to see another order of magnitude or so in the sample size before I believe this unconditionally.
Just off the top of my head, I note that there are over half a billion Hindus in India, and I’d guess that at least half of them are strictly vegetarian (though non-vegan). Are these Indian women generally having almost 5 girls for every 4 boys? Wouldn’t we have heard about this? I remain dubious.
Hi, i’m neither a vegetarian or a mother, but I’d like to contribute.
Most studies are done to prove something, in this case the predisposition of vegetarian mothers to give birth to less males than females.
While the study may point to ‘vegetarianism’ as being a contributing factor, it shouldn’t be taken as being the most important factor, if indeed there is one.
I worked with a sociologist and statistician for a while.
“You can infer anything you wish by playing with the numbers”.
Yes, and if it doesn’t work the first time, just change your alpha level so that you are now 92% sure instead of 95%. Man I hate that about statistics.
Swiddles, you probably already know that their sample group was not only very small, but also they didn’t factor in smoking/non-smoking. They just barely mentioned in passing that “oh, most of the vegetarian women didn’t smoke”. They also didn’t mention overall health of all the women, any pre-existing conditions like diabetes or heart problems that could possibly affect their potassium/calcium levels.
Also, the whole article was written to be as sensationalistic as possible, quoting one of the authors right at the beginning, “We were really surprised!” That’s “sound bite” journalism, not serious science.
It’s also important to note that this was a press release written by the authors of the study themselves, not researched by Reuters and then posted. Reuters pretty much just checks to be sure that any articles submitted are written by real people (not hoaxes) and then they just post it. They don’t care about the science involved.
Also–they didn’t explain how they came by their definition of “vegetarian”. Look at all the threads we’ve had, arguing over vegan/vegetarian/lacto-ovo etc. If all they did was ask the women, “Are you a vegetarian?” and the women said yes, that wouldn’t really prove anything. Maybe some of the women who claimed to be vegetarians really ate meat “Oh, just once in a while,” or didn’t really understand what the researchers meant by “vegetarian”. Maybe one side of the table is meaning “strict vegan” and the other side of the table is interpreting the word to mean “fish, eggs, and dairy, but not red meat”.
So the “study” doesn’t mean doodly. Just because it’s on a Web news service doesn’t make it gospel.
hmmmm… my mother is a meat eater - I’m the oldest of 5 (4 girls) My mother-in-law is also a meat eater - she has 3 sons.
Personally, I don’t believe in statistics… or electronics… or a fair and impartial jury… can I go home now??
cmkeller said:
" 2) Even after conception, while the X or Y chromosome from the sperm is a major factor in determining the child’s sex, this genetic predisposition can be overridden in early stages of fetal developpment by severe hormonal imbalances in the mother. "
whoa,
that is contrary to anything i have ever heard! Are you saying that there are some XY’s that become girls??!!. REAL girls and not hermaphrodite or some such?
You may be entirely correct here (hell, what do i know about biology), but this seems to be an exceptional claim.
While it’s posible that the X or Y differential could occur prior to conception, it seems unlikely. If the effect is real( and the numbers given, an ~12% difference in the probability of a boy over 400 samples, seems signifigent ), a difference in the probability of carrying to term is probably the explaination. The question would be whether vegitarian mothers have an Increased probability of spontaniously aborting boys (relative to thier carnivorous sisters) or a decreased chance of aborting the girls. That would be a much more difficult thing to determine.
Oh well , i guess i didn’t have much to contribute, but that statement by cmkeller threw up a red flag…
Before examining that question, we’d have to factor in the fact that aborting female fetuses is something of a cottage industry in India. There was recently a “60 Minutes” report detailing the tragic fact that although much of India has no basic medical services, there is an ultrasound facility on nearly every block, so that women can find out beforehand if they have a female in utero and abort it. Out of several thousand abortions performed in India last year, only 4 were male fetuses.
Luckie, I know a person who is now a woman, who was a man. She is genetically XX, but her body developed incorrectly in utero and she came out male.
The very interesting thing was that, because she was genetically female, the insurance company paid for the sex-change operation to make her anatomically female. Lucky her
I have no idea how often this happens. Anyone out there who can quote statistics?
The testosterone produced by the fetus, triggered by the Y chromosome creates the male baby. If the fetus does not correctly produce the testosterone, it will be female. There will be a vagina, but no uterus. And the testes will not have fallen out of the body, so there will be two non developed testies inside the baby. Jamie Lee Curtis (I think that is the right name) has this syndrome. She has an XY karyotype.
Sorry I forget what it is called and I do not have stats.
