General Question

jmeeker98's avatar

Can a man be predisposed to have only (or mostly) children of a certain sex?

Asked by jmeeker98 (38points) May 6th, 2010

I’ve heard stories of men only being able to have children of a certain sex, King Henry VIII having only girls, for example. I was wondering if this is scientific/genetic, or if it’s just a “hit-and-miss” scenario. (I’m particularly interested because my husband’s family has nothing but boys in his generation & their children, and I’m really wanting a girl after having 2 boys! haha.)

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45 Answers

filmfann's avatar

There is a statistic that more boys are born during wartime than girls. I was always amazed by this.
It turns out that scientists have recently discovered that women who eat healthy have a larger amount of girls than boys.
The conclusion would be that during war, many men are gone, the women’s eating habits aren’t as good, and more boys are born.
It is too late to change the sex of your child by eating poorly, but it may explain why your family has a lot of boys.

j0ey's avatar

I have heard that more athletic men are more likely to have girls…....but that doesn’t really explain King Henry VIII…...

slick44's avatar

I dont think so. Honestly i think its all up to chance. We have all boys in my family as well, or we did . My son and his girl have just had a girl. Thank god. Too many young men running around here, finally a little girl.

casheroo's avatar

@filmfann I read something similar, I can’t find the article..but it said how women who eat cereals (which usually have high sugar) have more boys (I think that’s what it said! I need to find it.)
I don’t know. I think it all comes down to which little swimmers get to the egg. I know female sperm live longer, so if the woman ovulates early/quickly, she’d have boys, right?
I have two boys, and in my husbands family it’s a good mix of both. His grandparents both had quite a few boys, then girls. note: I’m not having a bunch of boys to get a girl..I’d go insane! lol

casheroo's avatar

Oh and I think King Henry VIII actually had two boys, didn’t he? They just didn’t live very long.

Adirondackwannabe's avatar

There is something about Y chromosome sperm moving faster, and X chromosome sperm moving slower but with more endurance. But when a guy unloads a few million swimmers, it’s pretty much a roll of the dice.

KatawaGrey's avatar

I think it also has something to do with the actual uterus. Temperature, mucous and as other has stated above, health of the woman in question can determine which little guys get to the egg. Scientists have also recently discovered that the egg is not completely passive and the first sperm to get to the egg might not even be the one to fertilize it.

@filmfann: It also has something to do with hormones. If the woman is around a lot of women all the time, her body will only be picking up female hormones and try to correct the imbalance by allowing a Y-chromosome sperm into the egg. I believe the reverse is also true.

bongo's avatar

There are some types of heredetory conditions which are linked to the sex of the child. females are less likely to show these conditions and can be carriers, as they have 2 x chromosomes this is masked. however boys only have 1 x chomosome therefore this can cause the condition to become apparent therefore the zygote is automatically miscarried in certain cases I cant rememer the name of any of these male based conditions where the zygote is automatically miscarried however i do remember covering it in 1st year genetics module in my degree.
also the time of conception has a slight effect apparently with ‘female’ sperm being able to survive longer (i think) in the uterus therefore if someone has sex just before ovulation is is possible that the age of the sperm accounts for a specific sex being more likely. It might be the other way round tho with ‘male’ sperm living longer in the uterus. This will only have a very small effect mind.

Adirondackwannabe's avatar

@KatawaGrey The egg is not completely passive? So, in effect women are telling us men what to do before day one?

JeffVader's avatar

@j0ey Actually…. it does. Henry VIII didnt become the bloated monster of a man until later in life. Up until his mid 30’s he was an increadably strong & athletic man. A good 6inches taller than the average, a champion jouster & tennis player.
Its abit saucy but you should look out for a drama series called ‘The Tudors’, may not be historically acurate, but is a very good portrayal of the big man :)

jbfletcherfan's avatar

I don’t think the woman has anything to do with it. I always heard that it’s the male sperm that determines the sex. But Dr. Ruth, I’m not, so….......?

sassy1's avatar

I look at my family my mothers one of five girls, and father four girls one boy. If I married a guy with mostly all boys on his side its still all 50/50.

wundayatta's avatar

This study says that eating more bananas and ingesting more calories makes it more likely that you will have a boy. This article adds that it should be a more fatty diet for boys. From the same article:

“Women who had sons were also more likely to have eaten a higher quantity and wider range of nutrients including potassium, calcium and vitamins C, E and B12. They were also more likely to have eaten breakfast cereals.”

An alkaline uterine environment increases chances of having a boy. Acidic for girls. Weight gain before pregnancy is associated with a slight increase in the chance of having a boy.

As others have said, Y chromosome sperm is faster yet shorter lived. X chromosome sperm is slower and longer lived. To take advantage of the difference between X and Y chromosome sperm, you identify the day of ovulation as precisely as you can. If you want a boy, you have sex on the day of ovulation, and use a position that places the sperm as deeply inside as possible. For a girl, have sex a few days before ovulation. A little more info about that technique.

What’s amazing to me is the number of people who have written books about sex selection techniques that are all based on easily available research. They must be selling these things, because there are a lot of websites out there dedicated to selling them.

DarkScribe's avatar

I have five daughters to three different women – and I have always been athletic. Maybe there is more than just coincidence.

anartist's avatar

I read long ago that coital position can have a lot to do with it. Basically girl sperms live longer and move slower. To have a girl a couple should have sex doggie style or some other position that has lesser penetration, so sperms have to travel a bit to reach the egg. To have a boy, deep penetration, like missionary style, is the better method.
Apparently this is called the “Shettles method”— Read this

hearkat's avatar

My father’s family tree had no girls for 6 generations – until me. I have 2 older brothers and 3 male cousins, so I was the only one. However, my brother now has a daughter, as well.

The_Idler's avatar

well if you assume 50/50 chances, the probability of having 5 children in a row all of the same sex is 1/32,
so not that improbable.

tragiclikebowie's avatar

My friends father, who has now passed, was incapable of having boys. Everytime his wife was pregnant with a boy (about 5–6 times) during their marriage, she would miscarry.

casheroo's avatar

@wundayatta Ah, you found the article that mentioned cereal..I knew I wasn’t crazy! lol

chocomonkey's avatar

Not what you’re wanting to hear, and maybe an old wives’ tale, but I’ve heard “Tom, Dick, & Harry” is statistically more likely than “Peter, Paul & Mary”... that is, once a family has 2 children of the same sex, it implies that for whatever reason, there may not be a 50/50 chance for boy/girl on the next one.

RocketGuy's avatar

I notice that pilots seem to have more girls than boys. I also read a survey that said that the gender of the second kid is 60% likely to be the same as the first. A man’s age may have something to do with it – I have 2 girls. I was 35 when we started trying to have kids.

Skaggfacemutt's avatar

I would say “yes” bur for different reasons than I am reading above. When I was young and starting a family, I read an article in a Women’s magazine that talked about increasing your chances of having one sex or the other. It talked about the potential mother’s body chemistry (acid or alkali) and depth of penetration. So I suppose a man would be more likely to produce only one sex of child if his style is to go deep (boys) or stay shallow (girls). And a woman can temporarily change her body chemistry by diet (milk and bananas for girls, salty meats and citrus juice for boys.) Anyway, it worked for me. I had girl, boy, girl, boy. Just what I was trying for.

JLeslie's avatar

Yes, some men just produce more girl sperm than boy sperm. The more boys a couple has, the more likely they will again have another boy. Same with girls. So, each time a child is born thats is the same sex as the previous child, up goes that mans stat that he will produce another of that sex the next time.

RocketGuy's avatar

There is a Chinese calculator/calendar that predicts gender based on conception date. It worked for 7 of 8 kids we checked. It looks like a bingo board, with G and B seemingly randomly placed. I have no idea how it works.

The_Idler's avatar

“It looks like a bingo board, with G and B seemingly randomly placed. I have no idea how it works.”


RocketGuy's avatar

Yep, GGBBGGGbGGBBBBGGB… No pattern, but correctly predicted 7 of 8 kids that we know!

hearkat's avatar

@RocketGuy: Other than artificial insemination, how can you know the date of conception?

RocketGuy's avatar

When one is married, one might not have sex every night :( so that is not hard to figure out.

hearkat's avatar

@RocketGuy: Maybe not every night, but hopefully several times a week? Unless one already has young kids – that was when I was least interested in sex.

The_Idler's avatar

It’s academic! The thing is random!

The number of possible outcomes of 8 “coin flips” is 2^8 = 256
The probability of any one unique outcome of 8 “coin flips” is one over 2^8 = 1/256

There are |8 C 7| = 8 possible unique outcomes, which would be “7 of 8” right
(the “miss” could be the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th or 8th “flip”)

Thus the probability of correctly predicting 7 of 8 babies’ sex is eight over 2^8 = 8/256 = 1/32

Now you may think 7 out of 8 is pretty good, even if it isn’t exactly a miracle at 1/32
The probability of achieving the same (or better) hit ratio with a larger sample (70+/80 for convenience) would be:

Σ|80 C (70,71,72,73,74,75,76,78,79,80)| = 1,910,882,785,907 …unique ways of getting 70+ of 80 correct
2^80 = ................................1,208,925,819,614,629,174,706,176 …possible outcomes


Which is ~1.58 * 10^(-12)
(Correct me if I’m wrong)

And that’s only for a sample of 80.

Skaggfacemutt's avatar

Okay, here is what I have heard. An alkali environment favors girls and an acid environment favors boys. Male sperm swims faster but runs out of steam faster, girl sperm is slower but lasts longer. So, ladies, you can do two things to give yourself a better chance of conceiving what you want. First, eat bananas and milk for girls; salty meats and citrus fruits for boys. Shallower penetration favors girls, deeper favors boys.

I guess your original question as to whether men really produce more X than Y sperm, I don’t think so.

By the way, I have four children and had them as girl; boy; girl; boy. Got what I wanted every time by using this method.

JLeslie's avatar

@The_Idler It is not equivalent to a coin flip. Some men produce more Y sperm than X and vice versa. That is why the stats of having another boy after already having three are something like 80%.

Skaggfacemutt's avatar

I think the reason is not the production of more X than Y sperm, but the fact that a woman’s body chemistry stays constant unless she does something to change it, and most married couples tend to “do it” about the same, too.

JLeslie's avatar

@Skaggfacemutt Let’s not blame the women for not producing a son. In history that was a nightmare in some cases. I agree with the boy sperm travel faster, and girl sperm live longer. So to get a girl some people try to have sex before ovulation. I think it is a fact that some men simply produce more Y sperm, sounds logical to me, more logical than women’s reproductive tract environment is always the same, especially over time comparing a 20 year old to a 40 year old. I don’t have a reference handy to back some men have more y sperm, but I guess I could try to find one.

Skaggfacemutt's avatar

Oh, I am sure that the mix isn’t going to always be 50/50 between X and Y. I just don’t think there would be a glaring difference, like a 20%/80% difference. I didn’t mean to insinuate that the sex of the child is the woman’s fault at all – the sex of the child is determined by the male and that’s a fact. There are a few things a woman can do to make things more favorable to one or the other, but there is at least one thing that a guy can do, too, like depth of penetration.

Adirondackwannabe's avatar

Men don’t produce more Y sperm than X sperm. When the cell splits, it’s always going to be one Y and one X sperm. It’s the alkaline acid and speed versus endurance factors.

JLeslie's avatar

@Adirondackwannabe Right, I guess that makes sense that through meiosis you get one y and one x, so are you talking about the environment, ph, in the female, or in the male before ejaculating?

Adirondackwannabe's avatar

Environment of the female.

Skaggfacemutt's avatar

Thank you, Adirondackwannabe. I didn’t have an answer to the production of X or Y sperm. I knew a scientist or biologist could answer that.

JLeslie's avatar

@Adirondackwannabe However, I know there have been studies of some men showing reduced X or y sperm related to chemical or radioactive exposure. I can’t remember which. So even if everything splits up right, it seems male “environment” might affect if certain sperms survive long enough to be ejaculated.

Adirondackwannabe's avatar

@JLeslie After I sent that I remembered there is an affect based on the age of the sperm. Over time, the pH of the guy does affect which survives longer. I just can’t remember if it works the same as the woman’s pH. I’d need to do some research on that.
@Skaggfacemutt Would you settle for an Animal Science major?

Skaggfacemutt's avatar

@Adirondackwannabe I knew you must be studying this sort of thing in some way. My daughter is a biology major, and her depth of knowledge of the subject amazes me.

timmybargmn's avatar

The female gamete is a haploid organism with 23 chromosomes (n=23) with one set dedicated to sex chromosomes which can only be an X. The male gamete is a haploid organism with 23 chromosomes (n=23) with one set dedicated to sex which can be an X or a Y. Very rarely are these numbers false producing sexual mosaics (i.e. XX/XXY children) from a nondisjunction during the stages of meiosis. The father always determines the sex of the child. Any particular diet, period of time, position…etc. is completely irrelevant, although if it were… it would need to pertain to the male and not the female. The Y chromosome gametes do not swim faster than the X. This type of bad science is akin to astrology and church rumors. Basically it comes down to a coin flip.
The females conclude which type of environment in which the embryo’s rapid mitosis occurs, and the sex of the child has already been determined at fertilization.
There are no conclusive studies that have shown men to be genetically predisposed to a higher concentration of X than Y or vice versa, although the possibility cannot be ruled out, just like it cannot be dictated either that this gene – if it were to exist or even pass – would be recessive or dominant nor if it is a random mutation present in one specific male.
My advice to you… don’t listen to people that give you old tales about eating banana flax, stand on your head 3 times a day, and have sex in cold water… it is all garbage.
Evolution and Biological Science should have taught you one thing: we are human… and that despite the millions of minute differences, we are all fundamentally the same. Although one person might experience a coincidence and relate it with science it is advisable to take it with a grain of salt and understand that things may seem one way but the simplest answer is usually the correct one… and that is:
No… mathematically and as far as biology is concerned(as of now) your third child should be female… but I’m sure you would have no problems if it were a boy.

Skaggfacemutt's avatar

Wow, my head is spinning! Well, I must be the luckiest woman in the world because I always got just what I wanted – four times! Girl, boy, girl, boy. But I am sure you are right – its a coin-flip.

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