The gender of the first 2 kids in your family

In My Humble Opinion
1

Growing up, I noticed that there was a disproportionately high number of families in my social circle whose first kid was a daughter but whose second was a son. It was a ratio so high it was hard to think of any explanation for it.
Mathematically, by throw-of-the-dice logic, there ought to be a 1/4 likelihood of each of the following happening in families with two or more kids:

  1. Son followed by son
  2. Son followed by daughter
  3. Daughter followed by son
  4. Daughter followed by daughter
    Just curious to poll Dopers to ask how things are/were in your family (“your family” can be defined as either the one you grew up in or the one you raise now.)

(Poll to come, assuming the board doesn’t 504 time me out…)

2

Are you by any chance a second child and a son yourself? And was ‘your social circle’ defined by families of your personal friends?

Because I am a first child, and an absolute ton of my friends are also first children. About 80% or so, rough guess. Generally I don’t find this out until we’ve already become friends. But people with similar life experiences so seem to gravitate to each other.

IOW the missing link may be … you!

3

I voted Daughter/daughter. That’s me, then my sister. I have a circle of 12 friends that I grew up with, and those results (including me) are 1)1; 2)4; 3)2; 4)5.

4

As I’m a boy, most of my friends growing up were boys. So the daughter first and second seems less likely, and two boys seems much more likely than either of the other boy/girl combinations.

5

On my side of the family, it’s predominantly son->daughter. This tendency holds through at least 4 generations, although several exceptions exist.

On my wife’s side, it seems to be the opposite, as far as I know.

Our kids were son->daughter as well.

I have no idea what this means genetically (if anything).

6

Here’s a study done in Denmark showing that 51.6% of first children are male:

https://watermark.silverchair.com/150-9-957.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAp8wggKbBgkqhkiG9w0BBwagggKMMIICiAIBADCCAoEGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMMQs1KCCjoQ2UxeExAgEQgIICUrjXasDBuxp_Nf3ICCMmnQy2DkbZYAA9Cxjzus9DuRWxVJ-Xwu1BaTmlVeTVt1Svq9JhaZl_H-1zVXvUslg9HTz_UgwUqQYYJcWZ6HxuE-M6UfZ2gK_iJauy35H79H40bso7geHdpjKlIg8lUnus8c6bzXbNIkO-G1obe8v18xmQuswUQyjNU5UXbuPxmGKe1NyGWOKDrfbtQYK2mRnaZHUQpbOJSrqyWAJDYz1xtuXYmxuT7xVexxVjIF-TxqQ766Q4UhLKsf4ul81SbdYzBS5DcZ3HVMXerp854zMi0OYgqn1Y1037OVwzHZ1yBrSMJUVKj_HwUfoUA3P4b0ZfdLYtuj7Ly1NMcWd8hIeiUM3UFV2tDxFTRWtvQBv_-i9CBphQuJPjlzrjx4HZ-Qy8lSTkDmqMxo3eCgrOmEoIBSlmTqsj9ArRo5AAFD8IoqPT7gN-fUGw5YkZQdVJjUNCMgqIhIlPLnVuhpdLCD6BTkbI7yOiCtXfj5o1M3VNyEL_6cRtkefLB-WXRJChVo_90aLDrJnumn5D1AByIILGYrIwptjSnrzEcSPAV5PY3fCdhiYJHben-saLC9MzRuVqOsPcVsB63-pvO62CbueyzknyOIj0_psMKUbbevIylOBJzb6OlTnAqNgIImmPMXn0itmVT4iiuWSbcXQViJDoycpuY75GIUOvbhFlmPcf3TYEVoJ9VZRIkhqgtbhJQ736q1jOe_TXl3UoCOu8OCdUxmgcASURqZJEf0WtNSUvUbaLO7xfEg7ApoYsLPsqjHuIgjLHqg

Here’s another study done in Denmark showing that the proportion of males is somewhere between 51% and 52% for every order in birth:

7

I voted “daughter first” then son as that’s how my first two kids were born. Same for my first two grands. However, when I was a child, I (male) was born first, then my sister.

8

Siblings – son, then daughter (I was #4)
My kids – two daughters

9

I have two daughters. My two sisters were born first then my brother and me.

10

I voted Daughter/Son because, growing up, it was my older sister and I and you said you noticed this while you were growing up.

In my current household, it’s two sons (but with different birth mothers so maybe that doesn’t mean much)

11

I know a family with six kids. All boys.

It makes you wonder if the chance of having a boy/girl is really 50/50 for all couples.

12

Based on a 1 in 32 outcome?

13

Son first, then daughter.

My experience, at least of the memorable kind, is that a lot of the families with “runs”, it’s usually a run on daughters, having kid after kid trying to get that son, until they eventually give up.

My wife’s family was that way, and several of the mormon households I grew up around were that way too.

14

Yes, I am a 2nd child and a son and my older sibling is a sister. My social circle wasn’t defined so much by whom I chose to hang out with but rather whom my parents did (they were involved in this educator’s association/society where a few dozen families congregated/arranged activities together.) The daughter-first-then-son pattern was so prevalent that comments were made about it.

15

My mom’s went boy, boy, boy (me), boy.

16

The gender make-up of the people taking the poll will skew the results. If I am a male and choose my parent’s family, then it’s more likely to have a male in the answer. You would have to figure out the probability the person doing the poll is one of the two oldest.

17

True, however, even though the Dope is 80% male (or something like that) it appears to be a fairly balanced survey outcome.

18

I don’t see a big difference in families with two children - speaking anecdotally here. Lots of BB, GG, BG, GB.

Where I sometimes see a difference that I have never seen verified, and might be difficult to check anyway, is in families of three. In my experience, if the family is GB or BG, they’re more likely to stop at 2, than if it was BB or GG. IOW, BBG and GGB is more common than BG+1 or GB+1.

I’m talking after easily available contraception, here. Before that not having more kids was a very different sort of decision to make.

I don’t think it is, and found some stuff about this many years ago, but all I can find today is wishy-washy stuff about wanting to have a son or a daughter and trying to influence it in some way.

What I read previously said something about acid or alkali environments in the womb affect whether male sperm or female sperm will get there. I’m not certain which way round it was, but acid environments killed sperm off more quickly, so male sperm, which generally swim faster, would be able to survive, whereas more alkali environments favoured the long-term female sperm, because the male sperm might have died before they go to the egg.

FWIW this was about the natural womb environment, nothing to do with the woo stuff about acid/alkali diets, which is what is taking over my searches right now.

There were also some better-evidenced studies that said some men tended to make more sperm of one gender than the other. Can’t find those either. However, this one does make sense, when you think about it - it’s not terribly likely that all men produce 50% female and 50% male sperm. It’s far more likely that there will be some outliers.

Also some genetic defects are sex-connected, and some of those defects stop a pregnancy coming to term; some of them stop an embryo from continuing very early on (probably more than we can even detect at this stage), so even if there was a 50/50 chance of conception, that doesn’t mean a 50/50 chance of being born.

19

As I am an only child, I can’t vote in the poll. But I can comment on this.

Both of my parents are the first child. My husband is the first child. My best friends since kindergarten? All first children. Probably some of that is that the area I grew up in was expanding at that time, so a lot of new families moved in at the same time as my parents.

20

While some of the thinks you describe may be plausible, I’m not aware of any evidence that they are significant. And prior to expending any effort on research we’d need to show that there is an observation that requires an explanation. Does anyone have a cite that the number of families with all-male or all-female offspring is overrepresented, i.e. significantly greater than expected by chance?