Do you think it's true that some men "only make boys"?

[willowtree81]

Or "only make girls"? Or is it really just completely random, so of course sometimes it works out like that?

(We have 3 girls, our friends have 4 boys- obviously this means nothing in itself, but just wondering..)

I have read somewhere that there are too many all boy family to explain using random distributions, but I can't remember where I read it, some kind of mathematical book.

No it’s not true - or at least never been proven. According to Dh (Dr) it’s a 50/50 chance each time.

I think so. More like some men producd many more of x or y so the odds are stacked that way.

It's to do with the quality of the sperm and whether the mucus in the vagina is slightly acidic or alkaline, giving the sperm carrying either the male or female chromosomes an advantage.

The sex of a baby depends on the chromosome carried by the sperm so the father always determines the sex. Not sure if some men biologically only produce viable sperm of one or the other.

This article reckons it's chance but with some factors influencing the outcome.

genetics.thetech.org/ask-a-geneticist/which-parent-decides-whether-baby-will-be-boy-or-girl

I have read that older men are more likely to have girls, because quality of sperm deteriorates and female sperm is hardier. Also smoking can have an effect?

I'm not sure about men but I do think some women can't carry one or the other. I knew someone who lost three boys but had two healthy girls, she was told her body just couldn't carry boys.

I think it’s variable.

Not based in fact and I don’t know if any studies have been done, but I don’t think it’s purely about men only producing one sex gamete.

Could be other things- a genetic incompatibility between parents that means one sex can’t fertilise, develop or implant. Or that the woman’s body can’t maintain one sex for some reason- hormone outputs, recognising it as foreign in the same was rhesus ab’s are?

So possibly particular couples are more likely to produce one sex. Possibly some evolutionary advantage as reduces the chance of inbreeding?

It's all based on X and Y some Ned have more of one than the other so will generally make more of one gender, others are 50/50 so it's likely to be either

I have a friend who has six boys, and went abroad from gender selection IVF to try and have girls. They had three cycles, and no girls retrieved. They were told that he just doesn’t create female sperm that is healthy enough to fertilise - I don’t know if that means that there are female sperm, but she seems convinced not.

I suspect it’s usually a combination of things, but that it’s not uncommon for a couple to collectively create an environment that favours one sex. I know a lot more people with a few of the same sex than I do people with both.

BIL is one of five boys... each of his siblings have between 1-4 kids each... who are all boys including my two nephews! What are the odds of that? Surely there must be some genetics at play there?

My husband's family has only boys. He has a brother and 6 male cousins. I have 3 boys, sil one boy. I was unsure whether I just can't carry girls as had several miscarriages or whether he only produces boys.

My DH saw a fertility Dr years ago with his first wife (about 35 years I think?). He had low sperm count and low motility. He was told if they did manage to conceive it would probably be a girl due to slow motility and the fact that x sperm survive longer than y sperm. I have no idea if that is correct or if thinking has changed but he did go on to have five girls (two with me) so maybe 🤷‍♀️

what are the chances of that?

Always the same. 50%. Give or take a teeny bit. The Laws of Probability are fascinating. Many problems plaguing humanity would be solved if everyone just spent 30 minutes learning them. So much confusion, bullying, shame, gambling, medical issues (like vaccination) disappearing in a moment.

Ok, I know I’m asking the impossible. At least, my opinion is about 60% unreasonable.

My dad is one of 5 boys, but his grandparents both had brothers and sisters. In the subsequent 2 generations, girls vastly outnumber boys. It seems a fluke more than anything. Family sizes are much smaller now as well, which might skew perceptions: much easier to conclude that some couples only have girls (for example) when they have three daughters. 80 years ago, there might have been another 5 siblings, which may have included one or more boys.

My great-grandparents had 7 girls, & then a boy! I can't imagine their reaction when girl #6 popped out (lighthearted of course!)

I did read an article on this once, apparently some men are more likely to make one sex than the other (but as a PP points out, it’s not possible that they only make x or y sperm - just that one type of their sperm is more likely to successfully fertilise).

Apparently more boys are born in the years following wars which kill a lot of men, and this is linked to the fact some men are more likely to produce boys and those men also statistically happen to be less likely to be killed in wars.

I’m not explaining very well, I wish I could find the article cos it was very interesting.

@Countdowntonothing

You cannot have more X or more Y.

Simply put, to make sperm, the cell splits in half (meiosis) so half the dna in each. Men have an X and a Y. So one cell would take the X and the other the Y. Equal numbers of X and Y sperm.

I cant believe i forgot how sperm are made I really remembervreading an article where there seemed to be more families than there statistically should be producing all boys for several generations. Perhaps the x is squiffy

I know someone who (tongue in cheek) claims that the sex of the children is the opposite sex of the parent who "wears the trousers" in the relationship. She has sons.

Friends of mine in NY went for sex selection since they already had two boys and wanted a girl. Unfortunately for them the husband only produced good quality male sperm so I do think some men can only produce one sex.

It's such bollocks and usually spouted by idiot men who think that "only producing male sperm" makes them more manly FFS

Like Countdown says, it's an equal split.

The only situation where a man could concievably produce only one healthy sperm is if they had a genetic issue affecting either the X or Y chromosome. That happens, but it's extremely rare.

Cervical mucous acidity changes throughout your cycle and is a bit less acidic when you're fertile, which is because mucous that is too acidic kills sperm (in general) it doesn't make a difference whether it is male or female sperm though.

Small sample size causes people to jump to conclusions and look for patterns where there isn't one. Try flipping a coin 4 times, over and over again. See how many "single sex families" you get. It's roughly a 1/8 chance. For a 3 child family it's 1/4 chance. It's not unlikely at all yet people seem to think it is

@froggydoggy

Friends of mine in NY went for sex selection since they already had two boys and wanted a girl. Unfortunately for them the husband only produced good quality male sperm so I do think some men can only produce one sex.

The second person to say this in the thread!

When they say this it doesn't mean that all of the sperm follows this pattern, it means that of the embryos they extracted, none of the female ones were viable.

They don't test the sperm and only pick the chosen sex. It's the same process as PGD which is where they DNA test the embryos and pick the healthiest (or the ones without the condition they are screening for) - you can also do this by picking the embryos of the preferred sex.

I'm not sure who is to blame, but DH comes from a male heavy family.

In three generations (PIL's kids, grandkids and great grandkids) there have been three girls (1 in each generation) and 13 boys. I think MIL secretly hoped I would have girls as I'm from a large family of girls.