Adult height is double what they are when two - surely rubbish?

[PollyParanoia]

Hello, people are always saying "you can tell how tall toddlers will be as adults by doubling their height when they're two". This is asserted as if it's a well established medical fact.
Now I've now idea what height my ds was when two as I didn't measure him, but I'd bet it was fairly wee relative to his friends. Now of course there are more important things in life than being tall, but I'm wondering what correlation there is between toddler height and final height. I can't believe that double-calculation as all the 2-3 yr old girls I know seem to be enormously tall, sometimes even three inches taller than the boys, and I don't suppose that they're all going to grow up to be six inches taller than all these boys with normal sized parents.
So, is my almost 3 ds going to be little because he currently is, or will he be his father's height (5'11 - I'm about 5'7)? Or are these things completely unknowable...
Pol

There is a gender adjustment you make but I can't remember what it is.

You could try this Polly and see if it helps

It's mean of parents' height plus two inches for boys and minus two inches for girls. I think. Which makes him 5'11. I'm just wondering where this double height factoid comes from though as looking around it does stack up.
Oh well, not exactly an important issue...
Pol

My dm told`me
I was 3'2 at 2 years old so was expecting me to be 6'4''! Nearly made it, I'm 5'11'!

Completely unknowable, and the formula has an unquantified (as in, "immense") error margin to it.

it's bollocks.

dp is 6ft and was the shortest in his class until about 11.

bollequese!

My BIL told me this fact and he is a Paedeatric Consultant so is fairly well trained in this things! I was 2.55 @ 2yrs so guess who gets calles short arse...

As far as the doubling the height tale goes, I'd heard that for girls you were supposed measure at 18 months, whereas boys shoud be measured at 2 years old. Not saying there's anything in it, just passing on what I've heard...

It is cobblers isn't it? Just looked at the red books of ds and dd and the av height difference between boys and girls at two is 1cm which wd make the av height difference between men and women 2cm, which it isn't.
I don't really give a toss what height he is, what interests me is the way that these myths spread among parents.So many sentences beginning "apparently".

My little boy was 3' exactly on his 2nd birthday, and his dad is 6', so we'll see.

I don't suppose it's an exact science though.

Sorry posted message about the red books before post about 18m for girls and consultant paed, but actually the 18m point sort of confirms my suspicion that these "facts" we share are a bit hit and miss, given that we've heard different supposed truths.
And maybe consultants are just as gullible?

PP - you are probably right - he thinks I'm supermum!

But I'm sure you are supermum - your name alone implies that you've got the first rule of sanity sorted.
While doing the bath-bed thing, I've been thinking about other scientific facts dolled out. I've often heard things along the lines of "apparently if you have two boys, then it's really unlikely your third child will be a girl", or "my doctor told me that if you have two girls, you only have a 10% chance of your third being a boy" etc. I actually saw a study which said this is total bollocks as every time your odds are 50-50 (or 51:49 boy:girl to be more exact).
Probably another thread altogether, but I'm obsessing over this "it's a scientific fact" thing.
Pol

well my sister was 3' at 2!

mum was heartbroken she was gonna have a daughter of 6ft.

sis is 5'3" - i think!

i was smaller at 2 but am now taller than sis!

i don't believe it!

ds1 is about 3ft at 2... i think he's gonna be taller than 6ft though... dp is 6' 5"!

MIL "calculated" both her children's & grandchildren's heights (fairly accurately)using this method. She said my DD would be 5'8 or 9 by measuring her at 18mths. She's now 18 and 5'7. She says to measure boys at 2 and girls at 18mths. I like old wives tales

Polly, you would think 50:50 every time (or 51:49) but some people apparently have a more favourable environment for one sex or the other (cervical mucus or something)...

dd was 3 foot 1 at 2
I am 5 foot 5 and dh is 5 foot 8
I very much doubt that we have a 6 footer on our hands. I'm guessing she will be tall, hit puberty slightly earlier than others and then stop growing.

I painstakingly got the red book, measured me, then dh and ds then did some calculations. Worked out ds will be between 5'3 and 6'3

we tried that calc thing too, with DS1, adn then realised that DH's parents are 5' 1" and 5' respectively and he is 6'2", so the error margin thing is immense. There was another thread on here a while back about growth spurts in puberty and lots of v short boys in particular seemed to take off in puberty very rapidly.

My dh was a tiddler and couldn't be in any sports teams as he didn't go through adolescence until about 16 or so. Obviously they all grow at different rates. I know a giant 3 year old girl (literally head and shoulders above contemporaries, always expected to act older than her age) and both her parents are average to short. They both say that they were very tall children then stopped and saw all their classmates overtake them.
Maybe I'm just annoyed that I didn't measure ds at 2.
Am amazed at snipersdad being a foot taller than his parents. Blimey, what were they feeding him (or what were his parents not being fed. War babies maybe).

Dh's mum swears it's true. she did both kids' height at two and it was accurate with each.

DD is a taller than average 3 year old and DP and I are quite tall I am 5'9 and he is 6'4.
When I did the red book calculation it said DD would be 5'10 which going by the women on my side of the family is likely as each generation ahs been a little bit taller but if we go by dp's family all of them on both sides apart from his mother aare tiny women.

I don't know why, pp, dh's sister is also v short - when the four of them walk in a line, they look like a giant 'L'.....