Sunday, 13 June 2010

Birth order and gender prediction - a totally unscientific survey

When I was pregnant with A and S, my mother said to me, "I think they'll be girls.  If you look at your friends you'll see that the second baby tends to be the same as the first.  After that, anything goes, but the first and the second are normally the same."

Now, to be honest, I thought that was a load of nonsense.  But then I looked around.  I'm a girl, my sister's a girl, then there's my brother.  B's a boy, then there are two more boys.  My mum and her sister are girls.  My dad and his brothers are boys.  I've got L and then A and S.  My brother and sister-in-law have girls.  My colleagues fitted the pattern, my uni friends do, and so do most of the new friends I'm making up here. It goes on and on.

So I find myself wondering whether it's true.  So I've done what every committed social science and scientific researcher does, and I've googled it.  And I haven't, after an intensive five minutes, found any proper research.  So I thought I'd do some improper research instead.

How about you?  Does your family (parents, siblings, your own children) follow this theory?  Or is it, as I first thought, yet another one of those wonderful myths about gender prediction (gold rings, round bumps, speedy heartbeats) that we really should have stopped repeating in the fifteenth century.  Write a comment and let me know, and I'll do a whizzy spreadsheet.... oh, and please do pass it on, the more info I have the more "reliable" the survey will be!


  1. I have a boy and a girl. Sorry.
    I also have a brother.
    And my husband is one 2 - the other is a sister. And she has 2 children - you guessed it - and boy and a girl.
    My best friend has a boy and a girl but one of my other closest friends has 2 girls.
    Enough research for you?

  2. From my own experience it's not true (OK yes, so I have 2 boys) but in terms of my own siblings, the order was girl, boy, girl. In terms of my husband's siblings, the order was girl, boy, boy, boy. With my mother and her siblings it was boy, girl, boy, and the list goes on....Lots of my friends have just one of each gender.

  3. Hmmmm. I have a girl and then a boy. I also have an older brother and I was born after him (I have a younger sister too).

    Also, in my group of 11 mums, quite a few of us have gone on to have 2nd children of the opposite sex to our first. 6 of us have one of each and 5 of us have the same.

    So not sure about this one!!! There are lots of people with only 2 children who have one of each sex.

    Though I don't know what the more usual is - if it's more common to have have 2 the same than 2 different.

    My husband is one of 2 boys, his mum is one of 2 girls, my best friend is one of 2 girls...

  4. I have a boy and a girl.
    I am one of three girls.
    My sister has a boy and a girl.
    My husband is an only (and adopted so we don't know)
    My Dad an only
    My mum an only (and adopted so we don't know)
    Best friend has 3 boys
    Other friend has girl, boy, girl, boy, girl
    In fact most of my ante-natal friends had one of each
    My husband says that it's always 50/50 chance. He once tried to explain the odds for me (when I was wondering if I was going to have a girl) but I'm a maths dunce. But I have heard that if you have two of the same sex, then the next one is more likely to be of the same sex again but I don't know why.

  5. I have 2 boys and I have just one sister, but my husband has a sister too. My mum is one of 2 and has a brother. My dad is one of six and has a brother just after him... In my family or surrounding it seems to be 50/50.

  6. in my circle of friends with two children, it's a mad mix of one each, two boys, two girls. No clear pattern. I don't believe it's more likely to have two of the same.
    As for us, let there be a surprise.

  7. Oh I love these 'scientific' prediction methods. My own personal favourite is that very-overdue babies tend to be girls - any takers on that one?
    I'm afraid to say my siblings and I scrap your theory as does my husbands family but we will see when we have a 2nd child if we can prove you right.

  8. Me: boy-girl-...
    My parents: girl-girl-...
    My husband's parents: girl-boy-...

    So no - sorry.

  9. Well, I'm an only child but:
    2 step sisters
    2 half sisters
    Ex fella has a brother
    other ex fella has a brother
    My mum has a brother (exception that proves the rule maybe?!)

  10. I'm one of three- girl, boy, boy
    My hubby is one of three- boy, girl, boy
    I have three- girl, girl, girl

    My parents:
    dad- boy, boy, girl
    mum- boy, girl, boy

    Hubby's side
    dad- boy,boy, girl
    mum- girl, girl, girl

    That would we about half fitting your suggestion...

  11. I've 2 boys and don't know for the next one. My husband is boy boy girl. my aunt is boy boy girl and other one is boy boy. My Mum is one of 4 girls (but the others are half sisters so not sure it counts). Dad an only. I have 2 brothers, but I'm the eldest so theory doesn't work there. Most my parents friends have one of each as their first 2. My friends seem to have one of each too - which is a shame for Luke who is desperate for another boy his age to play with!

  12. Guess you say it was true for us with 2 girls then a boy .
    There was only my sister and i so who knows what a third would of been and my dad it was 4 boys .
    My mum is second youngest of 12 but no idea what order

  13. I have 2 boys.
    But my sister has boy girl and my brother in law has girl boy.
    I have read somewhere that if the Dad comes from a family with lots of boys, you are more likely to have boys. Don't know if this is backed up by any science though!

  14. I am one of three - boy,boy,girl
    I have three - girl, boy, boy,
    My brother has two - girl then boy
    My hubby is one of four boys.

  15. Ok I am little late to the proceedings but yet again I am going to dispel your theory. Not that I am enjoying this at all! I have a girl, a boy and then two girls. Maybe it's a genetic thing. Or just a fluke!

  16. ooh, I loves a bit of science me *dons white coat and goggles*
    my dad was one of 2 boys, mum one of 2 girls
    my parents had 2 boys then 2 girls then a boy
    I have two girls.

  17. I have 2 boys, 2 girls and then a boy and I know lots of people that follow your theory....from the comments above seems to be a mix doesn't it. :0S

  18. I am one of two - with a younger brother. Interestingly, I remember a lot of my friends at school also following the "one of each" pattern.

    I now have two girls, and find that 90% of the "peer parents" I know do follow your "second one is the same as the first" theory. Make of that what you will!

  19. Sorry, hit the send button too quickly. I do remember reading somewhere that it was scientifically proven that if you had a girl first, there was a slightly higher chance your next one would also be a girl, but this did not apply if your first was a boy.

  20. I am one of three - girl, girl, boy
    My four children are - boy, girl, girl, girl
    My OH's side - girl, boy, boy

    I heard that when it comes to having large families - if you have more than one of a certain flavour - you are more likely to have that same flavour again. Does that make sense? So after I had my third child who was a girl - my fourth was more likely to be a girl too - which she was!

  21. I am one of 2 - both girls (I'm the eldest)
    I have 3 - G, B, B
    My daughter has two girls

  22. Hooray! Thank you all for responses. I'll be getting on with a whizzy graph in the next few days.... Come back to check it out!

  23. Ok, so no whizzy graph, it would just have been a pretty rubbish bar chart anyway, but.... here are the results....

    I got told about seventy-one families (I included mine and B's children and siblings, and his brother and his children, but no-one else I knew, because I thought that would skew things unfairly).

    Of those seventy-one families:

    Thirty had different gender first and second children

    Forty-one had the same gender first and second children.

    So, on a ridiculously small sample size, it does seem to be slightly more likely that your second child will be the same as the first.

    That said, as Deer Baby says, it is, in terms of how the baby's actually made, always 50:50 what each baby is, so it's still probably a load of guff.

    But thank you for helping me work that out! I had fun!

  24. My family:
    (All my siblings are half)
    Mom's kids: Boy, girl, girl
    Dad's kids: Girl, girl, boy
    My kids: Girl, boy, boy
    My maternal grandma: Boy, boy, girl
    Paternal grandma: Boy, girl, boy
    Hubby: Boy, girl
    My brother: Boy, boy
    My Sister: Boy, boy
    My ex: Boy, Boy
    Brother in law: Girl, girl
    Daughter's grandma: Boy, boy, boy
    Son's grandma: Boy, boy, girl
    Best friend 1: Boy, girl, girl
    Best friend 2: Girl, boy

  25. Which bears it out again interestingly - not a hard and fast rule but, anecdotally at least, slightly more likely...


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