Mother's diet can help determine sex of child: study

Wed Apr 23, 5:07 AM ET

PARIS (AFP) - Oysters may excite the libido, but there is nothing like a hearty breakfast laced with sugar to boost a woman's chances of conceiving a son, according to a study released Wednesday.

Likewise, a low-energy diet that skimps on calories, minerals and nutrients is more likely to yield a female of the human species, says the study, published in Proceedings of the Royal Society B: Biological Sciences, Britain's de facto academy of sciences.

Fiona Mathews of the University of Exeter in Britain and colleagues wanted to find out if a woman's diet has an impact on the sex of her offspring.

So they asked 740 first-time mothers who did not know if their unborn foetuses were male or female to provide detailed records of eating habits before and after they became pregnant. The women were split into three groups according to the number calories they consumed per day around the time of conception.

Fifty-six percent of the women in the group with the highest energy intake had sons, compared to 45 percent in the least-well fed cohort.

Beside racking up a higher calorie count, the group who produced more males were also more likely to have eaten a wider range of nutrients, including potassium, calcium and vitamins C, E and B12.

The odds of an XY, or male outcome to a pregnancy also went up sharply "for women who consumed at least one bowl of breakfast cereal daily compared with those who ate less than or equal to one bowl of week," the study reported.

These surprising findings are consistent with a very gradual shift in favor of girls over the last four decades in the sex ratio of newborns, according to the researchers.

Previous research has shown -- despite the rising epidemic in obesity -- a reduction in the average energy uptake in advanced economies. The number of adults who skip breakfast has also increased substantially.

"This research may help to explain why in developed countries, where many young women choose low calorie diets, the proportion of boys is falling," Mathews said.

The study's findings, she added, could point to a "natural mechanism" for gender selection.

The link between a rich diet and male children may have an evolutionary explanation.

For most species, the number of offspring a male can father exceeds the number a female can give birth to. But only if conditions are favorable -- poor quality male specimens may fail to breed at all, whereas females reproduce more consistently.

"If a mother has plentiful resources, then it can make sense to invest in producing a son because he is likely to produce more grandchildren than would a daughter," thus contributing to the survival of the species, explains Mathews.

"However, in leaner times having a daughter is a safer bet."

While the mechanism is not yet understood, it is known from in vitro fertilisation research that higher levels of glucose, or sugar, encourage the growth and development of male embryos while inhibiting female embryos.

http://news.yahoo.com/s/afp/2008042...dietsexchildren

http://journals.royalsociety.org/co...60687441pp64w5/

Huh? Are they saying people are eating fewer calories?

Yes, but that isn't true in the US overall. See page 2. http://www.ers.usda.gov/publication.../frvol25i3a.pdf

That is not to say that there is no link. I'd be interested in seeing a breakdown that went past calorie intake to macronutrient intake.

*falls off her chair laughing her ass off, making every person in a 100' radius of her office poke their heads out and wonder what space aliens have overtaken her body and caused an apoplexy*


these guys need to go back to high school health class. the female has absolutely no control over and no input in whether the baby she carries is male or female. all eggs carry the X chromosome. it's the sperm that carry the X and Y chromosomes. gender of the baby is determined at the moment of conception, based on whether the egg is fertilized by a sperm carrying an X or Y chromosome.

it wouldn't matter one whit what the mother ate before or during pregnancy. we aren't alligators where the environment surrounding the offspring has an impact on sex.


but the embryos were ALREADY SEXED before messing with their growth and development.

freaking morons.

For this to be true, a female's nutrition status would have to affect at least one of the following that I can think of off the top of my head -

1. which sperm makes it to the egg
2. which embryos are more viable

What would be the mechanism for that? I have to admit I'm very skeptical.

ETA: I see Kvon posted while I was posting.

What the mother ate can very well be part of determining the sex of a child. The environment sperm travels through is dependent on the mother, and it is well known that there is a difference in motility and some fine movement between sperm carrying X and Y chromosomes.

I think there's some good animal examples of stuff like this I just can't remember what animal(s) do it.

I think it's already known that female embryos are stronger as are female children, less likely to die, more viable, etc. I've heard about 50% (I might have that number wrong) of embryos are spontaneously aborted at such an early stage that no one was even aware they were pregnant. So even a slight skewing of that number towards one gender would be significant.

I think you hit the nail on the head, either one or both of those pathways would be how the gender could be favored.

Ah! My brain is better than I thought: http://www.nlm.nih.gov/medlineplus/...icle/001488.htm
"It is estimated that up to 50% of all fertilized eggs die and are lost (aborted) spontaneously, usually before the woman knows she is pregnant. Among known pregnancies, the rate of miscarriage is approximately 10% and usually occurs between the 7th and 12th weeks of pregnancy."

Maybe they should have been asking the males what they ate?

They used an unreliable data collection technique:



How detailed?

Right, so the mother's nutritional status would have to affect something that affected sperm in such a way as to segregate the X's from the Y's. A change in cervical mucus consistency, making it harder for the sperm to swim? A change in pH that affects the more fragile Y's but not the hardier X's? Or is there something about the egg itself that makes it more "accepting" of X-carrying sperm?

Or we could be barking up the wrong tree and it could be about the environment that the embryo grows in that is somehow predisposed towards female embryos for some reason depending on the mother's nutrient status.

I just didn't find the mechanism the article put forth very plausible.

This is Yet Another Epidemiological Study (YAES). Correlation does not equal causation. For all we know, the sex of the foetus could be determining what the mother craves to eat.

I mean, who's looking at these studies, vegans?

No, you have it backwards. The sex isn't changed after conception so it could hardly change what she wants to eat. It is what she eats, or doesn't, before conceiving.

Seems like there should be some records of births after famines. I wonder what they show? Wait... I've read about this. I'll go look.

Ok, I knew I had read this information before: Famine link to girl births

Women don't develop weird food cravings during pregnancy. It's an illusion.

After you've been pregnant (LOL) come back and let us know....

I can see how it may be possible - the environment the sperm travel through and/or the thickness of the outer layer of the egg it must penetrate may be such that an X or Y sperm becomes favored to "win" getting in to fertilize the egg.....or it could be viability of the XX or XY embryo that is the determining factor of the fate of the outcome - if the environment is favoring one way or the other, an embryo may be spontaneously aborted before the woman knows she's pregnant and then that would skew the percentages of boys vs. girls born over time.