AIBU to ask what sex isn't baby?

[Savuti]

I am pregnant with my second, AIBU to ask if my next baby will be the same sex as my first or more likely (anecdotally rather than scientifically) to be different.

Most sibling sets I know are the same boy/boy or girl/girl.

Do you agree? Or am I getting the opposite sex this time round?

Just for 'fun'

My parents: b, b, g, g
Me: b, g
DSis: b, g
DBro: b, g
(DBro 2 has no dc).

Anecdotally, I’d say most families I know are mixed b/g, but this is probably as much a function of who I “chose” to know as actual data and statistics.

Me and my sister have one of each.

Girl then boy.

My mum has two girls before having a boy 23 years later.

Someone I know has 3 boys and others I know have two boys before having two girls.

It’s completely random

My sister and I are both women.

You hope.

For what it's worth, we have one of each. My younger sister has 3 girls, my husband's younger brother has 3 boys ...

My ex-partners mum had 5 boys, she now has 5 grandchildren all girls.

Anecdotally, you seem to get the opposite of what you're expecting but are happy with whatever you get. So, if you always thought you'd have two of the same your second child will be different. Or, if you always thought you'd have one of each, you'll either get the same again - or twins. None of my friends should buy lottery tickets; predictions are always way off.

if your first is a son you are marginally more likely to have a second son because having had a previous pregnancy with a male child is slightly more likely to trigger a miscarriage of a female foetus but the magnitude of the effect is very low so it's still pretty close to 50:50.

I'm one of a group of six friends, all with children under five. Up until recently we all had two children and we all had either two boys or two girls, nobody had a mixture. So that makes me thing maybe you are more likely to have the same sex?

I am the only one now who has a third child and I got a girl after having two boys. So I'm the only one with both sexes.

Interestingly, everyone I know personally who has three children also has two boys and a girl.

My mum has two girls
My MIL had boy, boy, girl, boy
BIL had BGGG
BIL had BBG
SIL had B

I’ve got a boy and a girl.

Nan: boy girl
Nan: girl boy
Mom: girl boy boy
Auntie: boy girl
Auntie: girl girl girl
Mother in law: girl girl boy boy
Sister in law: girl girl boy
Me: boy boy boy girl

Quite interesting to see it all written down actually! No pattern whatsoever in our family

I always thought scientifically it 'resets' but anecdotally didn't match up to what I 'see'

That's because, even if you think about the dozens of people that you know, the sample size is too small to definitely have to be 50/50. You only need a 'run' of a few certain combinations to skew the results. You also are not including any DC that you don't know about, eg any that have been aborted or have miscarried.

On a population level there is probably no definitive rule - there might be a few effects that marginally cause some people to only have boys or only have girls, but they're probably too small to be noticeable outside the random chance of boy or girl. There might have been scientific studies looking at this, but it would have had to look at thousands of randomly chosen people to have any scientific weight with quite a detailed analysis of the statistics.

If you want to illustrate this, spend a few minutes tossing a coin and write down the results. If you do enough coin tosses (hundreds) you will tend towards 50/50, but there's nothing to stop you getting several heads or tails in a row, or a run of alternative heads and tails, but you will see that each time it is totally random whether you get a head or a tail, and the sex of DC is probably the same, or very close to 50/50 by chance.

Interesting

Grandma 1 - BB
Grandma 2 - GG
Mum- GG
Aunt 1 - GB
Aunt 2 -GG
Sister - BBB
Me - GGGBG
Cousin - BB

So seems same sex patters dominates our family with only one example of the second born being opposite sex to the first.

Ok, anecdotally, I’m 1 of 5 (G,G,B,G,G). Each of us have two DC
DS1 had G, B
DS2 had B, B
DB had B, G
DS2 has G, G
I had B, G
Three mixed pairs and two same sex

Sorry, second DS2 should be DS3

I 100% guarantee this is a true story. No B/S.. you couldn't make it up.

I was working with a girl (V) in her late twenties when her friend's partner came in and told her they had just been for a scan...

V: Is she having another boy?

Friends DP: No, not this time.

V: What's she having then?

And she couldn't understand why I was crying with laughter.

I seriously considered Tena Lady that day!

I had girl girl
And of my closest friends
2 had girl girl
2 had boy boy
2 had boy girl
2 had girl boy
I only realised that now!

I’m one of a girl/boy set, as is DH. Mine are girl, boy, girl. Best friend has boy, girl, boy, girl. I know lots of same sex siblings, and lots of different sex siblings.

All eggs (unless there’s a problem with ‘production’) pass on an X chromosome, the sperm contribute either X or Y, so if there’s any pattern it would pass down the male side of the family (the exception is non-identical twins which come about when the mother releases 2 eggs instead of one)

DFiL and siblings are BBGB
DH and siblings are BB(G)B (his sister was stillborn at term)
DBiL has BB
We have B (plus my daughter from a previous relationship)

As someone else has said, there is a difference in swim speed and life between male and female sperm, and I don't know whether all men produce an exactly even amount of both - it could be that a particular man is more like to father one sex or the other, in which case you would be more likely to have the same sex (assuming same father). I'm thinking of families where you have 6 girls and no boys for example, it's possible through random chance but there could be an influencing factor.

But only two children isn't enough to see much of any pattern, you might as well flip a coin.

Of my generation (in my family born between 85 and 97) if a girl came first she was followed by a boy, if it was a boy first, bar one set of cousins the following child was a boy (this is from 11 siblings if that helps) all the next generation (7 so far) are boys except 1 girl and she is the youngest of 3.

Dh has one older sister and I have one younger brother, before we had ds I thought we'd follow that pattern and have a girl first, we didn't.

As someone else has said, there is a difference in swim speed and life between male and female sperm

This theory was recently discredited... it was based on a false assumption.

I know mostly boy/girl siblings!!

I have read that families with all boys or all girls (more like 4 or 5 boys / girls, I don’t mean 2 b/g) are more common than they “should” be if the odds each time were really 50/50.

One side of my family have produced a girl then boy first for the past 50-odd years (where a second birth occurred, sime hirls are only children). We're probably skewing the stats though.

*some girls