It's genetic, but with a wider variance and less heritability than you might expect. The scatterplot is from a swedish cohort study that investigated the relationship between the parental heights and the height of their offspring at maturity.
For cohorts used in this graph, the fitted formulas were: y = 45.99 cm + 0.78 x (boys) y = 37.85 cm + 0.75 x (girls)
where y=predicted height, x=midparental height
and the 95% CI from predicted heights were about +- 10cm (3.94 inches)
Here's the scatterplot for boys' heights on the y-axis, with midparental height on the x-axis (axes are normalized to 'standard deviation scores (SDS)'. The three vertical lines illustrate three 95% confidence intervals.
Note how when midparent height decreases by 1 SD, the CI intervals still overlap by 82%, which is much more than you might expect.
Let's put that in perspective for US data, where we have: -SD of heights is about 7 cm (2.76 inches) -Average Male is Height: 1.757 m (5'9.2) -Average Female is Height: 1.615 m (5'3.6)
Midparental height with a 0 standard deviation score (SDS) would mean two average parents: 5'9.2 man and 5'3.6 woman (175.7 cm + 161.5 cm). Their son would be predicted to be 5'9.9 (95% CI: 5'5.9 - 5'1.8) Midparental height with a -1 standard deviation score (SDS) would mean two short parents: 5'6.4 man and 5'0.8 woman (168.7 cm + 154.5 cm). Their son would be predicted to be 5'7.7 (95% CI: 5'3.8 - 5'11.7) Midparental height with a +1 standard deviation score (SDS) would mean two tall parents: 5'11.9 man and 5'6.3 woman (182.7 cm + 168.5 cm). Their son would be predicted to be 6'0.0 (95% CI: 5'8.1 - 6'4.0)
From an individual woman's perspective, her height would be height fixed. Choosing a man 1 SD above or 1 SD below the mean would only change their midparental height SDS up by 0.5 or down by 0.5.
So to her, 'choosing the tall guy' only makes a very small difference in their son's height: 1.07 inches
Likewise, being "the tall guy" only gives the same small advantage to your son's height, unless you also pick taller women.
In general, the formula 'y = 45.99 cm + 0.78 x' means that your son only gets about one third (0.78*0.5=0.39) of any given height increase from your partner. In this context, the observation that the slope isn't exactly 1 is an instance of regression to the mean. en.wikipedia.org/wiki/Regression_toward_the_mean
Explain to me like I'm a blabbering idiot who doesn't have any idea what you're talking about
Hudson Baker
>Explain to me like I'm a blabbering idiot who doesn't have any idea what you're talking about 1) If you are choosing your partner's height partially based on not wanting your sons to be short, you'll probably be surprised that going from a 5'9 partner to a 6'0 partner (3 inch increase) only changes the average height of your son by 1 inch.
2) If you are expecting two short people to have short kids and two tall people to have tall kids you might be surprised how much the range of heights overlap (these are the 1st and 3rd red lines in )
3) The minimum height of both parents so that 95% (or whatever) of your kids aren't "short" (however you define it) would also be higher than you expect, possibly much higher. I didn't actually calculate these values. If someone is interested I can do a sample calculation.
Matthew Stewart
now give me the chart for /fit-lit/ parents
Cooper Cooper
I'm 6'2, i want a son that's at least 6'4, what's the minimum height woman i should aim for to make this likely? Thanks big brain fren
>I'm 6'2, i want a son that's at least 6'4, what's the minimum height woman i should aim for to make this likely? Thanks big brain fren You need a wife that is 6'2.5 to get the average son that is 6'4. If you want 95% of your sons to be 6'4, then your wife has to be 7'0.5.
Huh I always suspected this was the case. Good to know that my bro science knowledge now has actual data to back it up
Ayden Barnes
I'm 5'11" Their mom is 5'8"
17 yr old son is currently 6'3" 14 yr old son is 5'8"
I fed them a lot of protein, so maybe that helped? (Chicken tendies or eggs for breakfast, packed their lunches, etc)
Brandon Rivera
wife is 173cm im 171 cm how talll my son go be? aint no way a son can be shorter than his mom right im think the 6 inch rule
Camden Wood
>wife is 173cm im 171 cm how talll my son go be? 180.15 cm +- 10 cm
Parker Wilson
>I'm 5'11" >Their mom is 5'8"
your sons are predicted to reach 6'0.3 (95% CI: 5'8.4 - 6'4.3)
>I fed them a lot of protein, so maybe that helped? (Chicken tendies or eggs for breakfast, packed their lunches, etc) Childhood diets high in animal protein are correlated with higher attained height. And I'm willing to believe there is causation.
Hunter Rogers
I'm 1.7m tall and my gf 1.65. But very different proportions, she has nice long legs and small torso, i have a longer torso and arms but my legs looks stunted (she says I look like a ape). What are the chaces our children will be taller than us? She's taller than both her parents while my dad was taller (1.85 but can't remember exactly anymore) and my mom is a womanlet
Jace Allen
Cool. Hopefully the height partially offsets their red hair when it come to women.
The ex thought I was a tyrant because I cared about what they ate.
Carter Perez
>I'm 1.7m tall and my gf 1.65 boys: 176.64 +- 10 cm girls: 163.475 +- 10 cm
>What are the chaces our children will be taller than us? A son or a daughter might be taller than you, but it's much less likely for the daughter who on average will be shorter than her mom. Your son will on average be taller than you, although the chance that he is shorter by an inch is still significant.
>She's taller than both her parents She's about 1.5 inches taller than the average woman, which is tall but still close to average. If both her parents were shorter by an 1-2 inches (or more) then her dad was very short, and her mom was at most average.
This is an instance of reversion to the mean, and it isn't unlikely. The more extreme a parent is, the more likely the child will be less extreme than the parent. In this case, the dad was so short it makes it very likely that his height was a combination of *both* short genes and bad luck (whether that was his childhood enviroment or random events in bodily development). His daughter can only be affected by the genes...she gets a fresh chance at the dice roll. Getting the same extreme luck as the dad was inheritely unlikely, while ending up close to average for her gender was much more likely.
>while my dad was taller (1.85 but can't remember exactly anymore) and my mom is a womanlet If your mom was 5'0 (152.4 cm) then their son was predicted to be 177.6 +- 10 cm, so you were below your expected height but still within the 95% CI (of course this changes depending on what guesses we use for your parents' heights). Again though, because you had significantly *bad* luck relative to expectations it also means that your latent height genes are probably *better* than most guys with your height.
Grayson Morales
I’m manlet 178 Gf is slavic giantess 187 How tall will sons be?
