# Likelihood of same sex children? **URL:** \ **Category:** Factual Questions\ **Created:** [February 5, 2013, 1:07pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384 "2013-02-05T13:07:56Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [February 5, 2013, 10:58pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/21 "2013-02-05T22:58:45Z")
> [@Doctor\_Jackson](#): > > My parents had: B, G, G > I have: B, G, G > Sister 1 has: G, G > Sister 2 has: B,G > > So the disposition in my familiy is to have a male first, followed by female(s). Except for sister 1, who has always been a bit of a rebel. > [@TheBori](#): > > Two data points: > My brother has four daughters (2 each from 2 wives) > I have 4 boys (one wife). > > It looks like my bro’s “X’s” swim better than his “Y’s”…and vice versa. You probably aren’t serious, but if you are, there’s too little data available in each of these cases to arrive at those kinds of conclusions, statistically speaking. You cannot extrapolate or draw broad conclusions with so little to go on. ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [February 5, 2013, 11:02pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/22 "2013-02-05T23:02:14Z")
> [@Kimstu](#): > > **panache45** ’s example brings in another factor: the so-called “stopping rule”, That can potentially skew the results for 2 child households but it won’t matter overall - as the article itself addresses. If everybody conformed to a stopping rule, the overall distribution of boys and girls would still be 50/50 (or close enough for guv’mint work). It’s actually a variation on the gambler’s fallacy to suggest it factors into the OPs situation. ---
**Author:** ![FuzzyOgre](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@FuzzyOgre](https://boards.straightdope.com/u/FuzzyOgre)\ **Post date:** [February 5, 2013, 11:21pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/23 "2013-02-05T23:21:01Z")
If you flip a coin 10 times, you will find runs of three are not uncommon. It is just as likely to be the first three. That is like having kids. So a lot of couples with three kids are going to have a set of one gender. It is random, but you are supposing a pattern that is meaningless in nature. ---
**Author:** ![barnhardt9999](https://avatars.discourse-cdn.com/v4/letter/b/ea5d25/32.png) [@barnhardt9999](https://boards.straightdope.com/u/barnhardt9999)\ **Post date:** [February 6, 2013, 12:41am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/24 "2013-02-06T00:41:39Z")
This is anecdotal, however I believe it to be true. My sister had a friend that was one of six brothers. From this line of men, there have been no female births for 8 generations. The friend is convinced that in his family men only produce Y sperm and the trait is passed on paternally. I imagine that a similar mutation which causes a man to only produce X sperm is possible but the trait would not pass on so it would be impossible to verify short of him having hundreds of children with many woman. ---
**Author:** ![RadicalPi](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/radicalpi/32/9806_2.png) [@RadicalPi](https://boards.straightdope.com/u/RadicalPi)\ **Post date:** [February 6, 2013, 1:44am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/25 "2013-02-06T01:44:57Z")
> [@astorian](#): > > I’m one of four boys. There was a 1 in 16 (about 7%) chance of that happening, just as there was a 1 in 16 chance my parents would have four girls. Moreover, with four children total, the odds of having at least three of one sex are quite high (which is arguable having “mostly” one or the other, if the standard criteria of 50/50 likelihood and Independence hold. Of the sixteen possible combinations, 2 have all one sex or the other, and 8 have three and one, making the probability 5/8, which is more likely than not. ---
**Author:** ![TaoPilot](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TaoPilot](https://boards.straightdope.com/u/TaoPilot)\ **Post date:** [February 6, 2013, 2:01am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/26 "2013-02-06T02:01:25Z")
My mom was the only one in her immediate family to have mixed gender children… Her grandmother had five girls, her mother had three girls, and her daughter had two girls. One of her sisters had two girls, and the other had three boys. My mother had one girl and then three boys. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [February 6, 2013, 2:18am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/27 "2013-02-06T02:18:20Z")
I’ve read in the past that a woman’s status appears to affect the gender of her children; higher status = more sons. Hard to tell how much of that is from the father though. I’ve also read that there’s a hypothesis that the X chromosomes regularly (on an evolutionary time scale) develop mutations that prevent the birth of male offspring, leading to the Y chromosome being the atrophied thing that it is as over time all its other functions besides “be male” are offloaded into safer chromosomes. Since everyone has Xs but only males have Ys, the Y is at a biological disadvantage. > [@Bob\_X](#): > > More than 50% of pregnancies terminate with early miscarriage that generally the woman is not even aware of, and some women may preferentially miscarry male children more often than female, or the reverse, for some reason (I don’t know if this is the case, just suggesting a reason why the above is not necessarily correct). Actually, it’s normal for a woman to miscarry more male embryos; more males are conceived than females because of that, but the numbers mostly even out by birth. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [February 6, 2013, 3:34am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/28 "2013-02-06T03:34:02Z")
Everyone should be forced to learn statistics in junior high school. ---
**Author:** ![April\_R](https://avatars.discourse-cdn.com/v4/letter/a/3da27b/32.png) [@April\_R](https://boards.straightdope.com/u/April_R)\ **Post date:** [February 6, 2013, 3:41am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/29 "2013-02-06T03:41:06Z")
I only have a brother, so one boy one girl for my parents. I had twins my first pregnancy, one boy one girl. We are due for another girl in June My husband comes from a family of 4 boys and 3 girls. So in our case it is pretty much 50/50 But I do know several families who are all boy or all girl, however most who go past two children have a mix of both. ---
**Author:** ![Tollhouse](https://avatars.discourse-cdn.com/v4/letter/t/e99b99/32.png) [@Tollhouse](https://boards.straightdope.com/u/Tollhouse)\ **Post date:** [February 6, 2013, 4:04am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/30 "2013-02-06T04:04:57Z")
a long time ago i read somewhere that the gender of the baby can also be somewhat influenced by the orgasm, if the man and woman did at the same time, or if the woman only did, man only did, etc Im sure there are old wives tales out there about other factors such as if the mom to be ate spicy food the night she conceived etc. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [February 6, 2013, 4:10am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/31 "2013-02-06T04:10:55Z")
Two girls in the male line of my family in the past hundred years. Nobody had a lot of kids, so maybe it’s not unusual. When my son was born we didn’t know, but when the doctor said “It’s a boy!” we both said “We know”. ---
**Author:** ![April\_R](https://avatars.discourse-cdn.com/v4/letter/a/3da27b/32.png) [@April\_R](https://boards.straightdope.com/u/April_R)\ **Post date:** [February 6, 2013, 4:44am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/32 "2013-02-06T04:44:09Z")
> [@Tollhouse](#): > > a long time ago i read somewhere that the gender of the baby can also be somewhat influenced by the orgasm, if the man and woman did at the same time, or if the woman only did, man only did, etc > Im sure there are old wives tales out there about other factors such as if the mom to be ate spicy food the night she conceived etc. :dubious:. ---
**Author:** ![Charley](https://avatars.discourse-cdn.com/v4/letter/c/97f17d/32.png) [@Charley](https://boards.straightdope.com/u/Charley)\ **Post date:** [February 6, 2013, 4:51am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/33 "2013-02-06T04:51:30Z")
For those offering explanations based on straight probability, I’m absolutely aware of the outcomes predicted by statistics. What I’m curious about is if there is research which suggests that it isn’t a straight 50% likelihood that children (particularly after the first) will be one gender or the other. For a given set of parents, could it be that, for them, the chances of them having a specific gender child are 55%, say, or 62% or whatever? So, that couple ‘have girls’ or ‘have boys’. The coin toss comparison doesn’t work IMO, since it assumes (correctly in that case) that each throw is independent of the others. To stretch the analogy to breaking point, I guess what I’m wondering is whether we have a loaded coin in the case of childbirth… are there some cases where the coin will almost always land one way or the other? The research **Der Trihs** mentions is closer to it, I think. ---
**Author:** ![Bob\_X](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@Bob\_X](https://boards.straightdope.com/u/Bob_X)\ **Post date:** [February 6, 2013, 5:05am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/34 "2013-02-06T05:05:38Z")
> [@Charley](#): > > What I’m curious about is if there is research which suggests that it isn’t a straight 50% likelihood It is certainly never a 50% likelihood: there is always some imbalance, with an excess of male births over females (nature wants the ratios to be about 50/50 by the age of sexual maturity-- in the meantime, boys die more often because they, you know, run with scissors etc.) but whether it is 54/46 or 51/49 or whatever is variable from one country to another, indicating that there have to be some genetic or environmental factors that change the likelihoods. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [February 6, 2013, 5:49am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/35 "2013-02-06T05:49:04Z")
This has been studied for years in horse breeding, and it is quite accepted knowledge that some stallions have a tendency to produce more of one gender. Secretariat, for example, had about an 8% lean toward female offspring. I don’t see why the same wouldn’t be true of human males. ---
**Author:** ![Reebevoli](https://avatars.discourse-cdn.com/v4/letter/r/49beb7/32.png) [@Reebevoli](https://boards.straightdope.com/u/Reebevoli)\ **Post date:** [February 6, 2013, 10:21am UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/36 "2013-02-06T10:21:23Z")
> [@RadicalPi](#): > > Moreover, with four children total, the odds of having at least three of one sex are quite high (which is arguable having “mostly” one or the other, if the standard criteria of 50/50 likelihood and Independence hold. Of the sixteen possible combinations, 2 have all one sex or the other, and 8 have three and one, making the probability 5/8, which is more likely than not. Surely there are only 5 possible combinations: 1. M M M M 2. M M M F 3. M M F F 4. M F F F 5. F F F F Corrections welcome. ---
**Author:** ![Reebevoli](https://avatars.discourse-cdn.com/v4/letter/r/49beb7/32.png) [@Reebevoli](https://boards.straightdope.com/u/Reebevoli)\ **Post date:** [February 6, 2013, 1:57pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/37 "2013-02-06T13:57:39Z")
Please ignore the above post :smack: ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [February 6, 2013, 4:04pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/38 "2013-02-06T16:04:46Z")
> [@Reebevoli](#): > > Please ignore the above post :smack: I like how they’re 4 hours apart. Like you posted the first one half asleep last night and then woke up this morning going “oh crap!” and dove for the computer. ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [February 6, 2013, 4:16pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/39 "2013-02-06T16:16:58Z")
> [@barnhardt9999](#): > > This is anecdotal, however I believe it to be true. It’s doubtful. The probability that I win the lottery is vanishingly small. The probability that _somebody_ wins the lottery is very high. Just because your friend just happens to be in the family that “won” doesn’t mean there’s a system to winning. After all, simple probability theory implies that with sufficient trials (in this case, families over several generations) it happens to some family somewhere with probability approaching 1, even if the boy/girl probability is independent from child to child and strictly 50/50. Going back to coin flipping (which I realize is not a perfect analog), just because you’ve flipped a coin heads 10 times in a row doesn’t change the odds on the next flip - it’s still 50/50. Also, the story sounds apocryphal. The records kept over a couple centuries were that good? Were there no actual female births or no reported female births? No female children who died at childbirth or miscarried? Or women who died giving birth to girls in childbirth? Such fine detail in family records is unusual over that many generations. ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [February 6, 2013, 4:32pm UTC](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384/40 "2013-02-06T16:32:35Z")
> [@Great\_Antibob](#): > > Going back to coin flipping (which I realize is not a perfect analog), just because you’ve flipped a coin heads 10 times in a row doesn’t change the odds on the next flip - it’s still 50/50. Well, yes, it possibly does. If you’ve flipped a coin 10 times and it’s landed heads 10 times, one of these things is true: 1. It’s a fair coin and you’ve hit upon the 1/1,024 chance of it occurring. 2. It’s not a fair coin at all, and the odds have been significantly skewed in favor of heads. 3. You’re in a Tom Stoppard play. Going back to the original example, you can argue that good record keeping over 8 generations is unlikely. And that may be true. But let’s assume it’s not, and there really have been only males for 8 full generations. You could choose to believe it’s because the odds are that someone, somewhere would have this happen to them. But I think the more likely explanation is #2 as above: you’re not playing with a fair coin. [Previous page](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384.md?page=1) [Next page](https://boards.straightdope.com/t/likelihood-of-same-sex-children/649384.md?page=3)