Considering the father determines the sex of the baby, how does this make sense?


http://dsc.discovery.com/news/2008/04/23/mother-diet-boys.html

April 23, 2008 -- 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....

HAHA what a load of BS. If that were true america would soon turn into an all male country.

hmmm, yeah. Vegetarians would have more girls.
How the hell did Victoria Beckham end up with 3 boys??

Considering the father determines the sex of the baby, how does this make sense?
Well, as Bill Cosby said, "It's not who had the Y chromosome, it's who had it last!"

But seriously, the man's semen contains both X's and Y's. Millions of them. What determines which one actually fertilizes the egg? It's not just the first one there. The egg sort of "decides" which one to let in. Is it so inconcievable that the "egg" would favor males, who eat more and take longer to mature, when times were good and females during lean times?

... It's not just the first one there. The egg sort of "decides" which one to let in. ...

How does it decide?

How about this ?

Skipping breakfast may mean your baby is a girl (http://www.reuters.com/article/scienceNews/idUSL2284780520080423)

I guess eating all that Rolo icecream from the container, blessed me with
2 healthy boys.

How does it decide?
New studies are showing that the egg plays an active role in fertilization, perhaps selecting the sperm with which to fuse. Clearly, this could allow for the egg to choose the sex of the embryo.
Ah, fertilization--that miraculous process to which we all owe our existence. Let’s review: First, a wastefully huge swarm of sperm weakly flops along, its members bumping into walls and flailing aimlessly through thick strands of mucus. Eventually, through sheer odds of pinball-like bouncing more than anything else, a few sperm end up close to an egg. As they mill around, the egg selects one and reels it in, pinning it down in spite of its efforts to escape. It’s no contest, really. The gigantic, hardy egg yanks this tiny sperm inside, distills out the chromosomes, and sets out to become an embryo.

Most studies clearly show that the sperm is attracted by the egg and activated by it, says Gilbert. http://discovermagazine.com/1992/jun/theaggressiveegg55

but how does an egg decide? Is there a coating on the sperm the egg prefers?

I don't think that's known yet. But the main variable between different sperm cells is whether they carry an X or a Y. What other criteria could the egg be using? Unless it's just random.

It's not just the father, when women have high testosterone levels their eggs are receptive to male sperm more than female...

Lets see the actually numbers from the study, and the sampling details, it could just be a badly done study.

It might be possible that women who have more energy to burn. Such as women who eat foods that are high in calories are more likely to have successful pregnancies with males. Female babies tend to more resiliant to "hard times" than male babies are. A woman who is starving, is more likely to have a girl because her body would most likely terminate a male pregnancy possibly before she even knew she was pregnant. I've heard it makes sense as an evolutionary strategy because female babies are usually stronger than male babies and infant morality rates are much higher among boys than girls. But once again I don't know if thats true, I just read it in one of my textbooks.

It might be possible that women who have more energy to burn. Such as women who eat foods that are high in calories are more likely to have successful pregnancies with males. Female babies tend to more resiliant to "hard times" than male babies are. A woman who is starving, is more likely to have a girl because her body would most likely terminate a male pregnancy possibly before she even knew she was pregnant. I've heard it makes sense as an evolutionary strategy because female babies are usually stronger than male babies and infant morality rates are much higher among boys than girls. But once again I don't know if thats true, I just read it in one of my textbooks.

two things run in females favors.

two sets of all chromosomes so defective genes can be compensated for if a functional copy exists on the alternate chromosomes, males lack this protection because they have only one X chromosome. this is relatively proven, for example the rate of male red-green color blind is at 6-7%, but the rate for women in ~1%, the chances for a women to be born with both X chromosomes having a defective red/green photoreceptor is very unlikely.

2nd advantages for a female fetus is theoretical, and evolutionary. Female babies and children are not cared for as nicely as male children, this natural sexism has likely hardened the female gender and weaken the male gender.

I think what I stated earlier might actually have some validity as far as male babies being weaker than female one's. Sperm cells that carry the Y chromosome are light and quick. They don't weigh much and they burn a lot of energy because they move so much so they don't live very long. Female sperm cells or those carrying the X chromosome are big, heavy, and strong they don't move very fast, but live much longer than male sperm. They also have no problem pushing the male sperm cells out of the way. Most of the women that I see on a daily basis that have medical problems with their fetus are almost always male fetuses. I don't know if that has any correlation, but I think its interesting.

I think what I stated earlier might actually have some validity as far as male babies being weaker than female one's. Sperm cells that carry the Y chromosome are light and quick. They don't weigh much and they burn a lot of energy because they move so much so they don't live very long. Female sperm cells or those carrying the X chromosome are big, heavy, and strong they don't move very fast, but live much longer than male sperm. They also have no problem pushing the male sperm cells out of the way. Most of the women that I see on a daily basis that have medical problems with their fetus are almost always male fetuses. I don't know if that has any correlation, but I think its interesting.

As far as I know the only weight difference between 'male sperm' and 'female sperm' is the weight difference between the X-chromosome ans the Y-chromosome. This difference is small.
Male babies have more medical problems because X-chromosomal malicious genes have no counterpart in males (only one X-chromosome) to 'correct' the problem.

I don't know about you, but I can see the difference just in their behavior. Sperm carrying the X chromosome don't bounce around as much and they are easily seperated from one another for people who want to have a specifically sexed child. Its a bit of a pricey procedure though. Sometimes I get to do it.

I don't know about you, but I can see the difference just in their behavior. Sperm carrying the X chromosome don't bounce around as much and they are easily seperated from one another for people who want to have a specifically sexed child. Its a bit of a pricey procedure though. Sometimes I get to do it.

Well, I'm not in that line of work, so I can't see them acting differently.
It could have to do with other things I imagine.

Female babies tend to more resiliant to "hard times" than male babies are. A woman who is starving, is more likely to have a girl because her body would most likely terminate a male pregnancy possibly before she even knew she was pregnant.
My youngest son was born at the University of Chicago. Like all my children, he was born via c-section and so had some fluid in his lungs. This meant he was in the nic-U (neonatal intensive care unit) despite weighing about 9 pounds. It was pretty funny to see this "giant" white baby in the nic-u with all these tiny black babies (premies).

Anyway, the nurses there said the same thing you did, except they went a step further. They said the premies that did the worst were the "wimpy white boys". .

The performance of male and female sperm seems anecdotal. Commercial sperm separation is achieve by labeling X and Y carrying sperm with a florescent tag that stick to the X or Y chromosomes or other sex chromosome determinate item and then separating the sperm via flow cytometry.

I think the difference lies how alkaline or acidic the female environment is. "Male" sperm survive better in one and "female" sperm the other.

I forget which is which.

However, I've never actually looked up the validity of that claim...

Is it possible for a man to his sperm be mostly one sex due to his diet?

No, that is not possible. Not unless the body reabsorbs "female" sperm faster than it does "male" ones (or vice versa, of course).

with all the birth defects in the world, why couldn't a man produce sperm of only 1 sex? There are sperm with 2 tails, sperm with 1/2 a head, why not 1 sex?

If its not possible, why?

Is it possible for a man to his sperm be mostly one sex due to his diet?

Its possible, but that does not have anything to do with the women's diet does it?

If it has to do with the man's sperm, the woman's diet has nothing to do with it. Maybe they are looking at the wrong person.

If it has to do with the man's sperm, the woman's diet has nothing to do with it. Maybe they are looking at the wrong person.

Or maybe what the women eats is what the man is eating too (assuming they are couples that have breakfast and diner with each other), you got a point they should run a control comparing sync and unsync diets between man and women affecting sex ratio of progeny.

with all the birth defects in the world, why couldn't a man produce sperm of only 1 sex? There are sperm with 2 tails, sperm with 1/2 a head, why not 1 sex?

If its not possible, why?
Well, you understand what characteristics of the sperm determine maleness, right? The sperm carrying a copy of the Y chromosome will more than likely create a male baby, and those carrying a copy of the X chromosome will likely create a female child. I say 'likely' because there are exceptions but those aren't directly relevant to your question since they occur during development in the mother.

Why can't a man have all male sperm? They can't because of the way the sperm cells are created: via meiosis. A sperm cell starts as a single parent cell, which contains one copy of the X chromosome and one copy of the Y chromosome. It duplicates all its genetic material, then splits (so, for a brief period it contains two copies of each the X and Y chromosomes). The two daughter cells each have a single copy of X and a single copy of Y. These two daughter cells then split again, but this time without duplicating the genetic material. This leads to 4 "granddaughter" cells in total -- these will develop into sperm cells. Two of them have a copy of the X chromosome and no copies of Y, and vice versa.

This is also the basic premise behind dominant and recessive genes, because you are splitting the genetic info between the germ cells. Each cell has two copies of chromosomes 1-22, so if you had one copy with one allele (say the dominant allele) and one copy had a different allele (recessive), you would end up with two sperm cells carrying the dominant allele and two carrying the recessive.

Again, unless all the sperm cells carrying the X chromosome were to die, it wouldn't be possible for men to create only "male" sperm.