Why are the younger generations so much taller

[Kisito]

I noticed that there were four main factors. 1: Genetics. 2, that the country is in peace time, it is not traumatic or post-traumatic. 3: Being close to the sea level 4: The birth rate is inversely proportional to the size of a nation.
Observe the netherlands and China. Genetics, trauma, sea level and birth.

 

[Thor]

I recall listening to a podcast on This American Life where they were talking about the chicken industry. Since the 1930s the weight of the chickens that were slaughtered had increased significantly. And the number of days to reach this development had decreased by about a third. I recall a comparison to humans where they mentioned that the same methods applied on humans would mean that the average kid would be 6'10" at the age of 12, weighing 250 pounds!

My father's 187cm (6' 2") and slender. The same goes for all his sisters. I'm 202 cm and also very slim. While my father was definitely tall for his generation it seems that I outgrew him more than the normal couple of inches. My mother has often told me that growing up I ate more or less nothing until the age of eight but I would drink about a gallon of milk a day. That may have contributed to my height but it's hard to make statistical inference based on a sample size of one :). Maybe it's just variation...