Several times I've heard people say knowingly that today's taller children are proof of evolution.
In reply, I point to second- and third-generation children of Asian immigrants who tower over their parents. Evolution doesn't work that fast. Evolution is a scientific fact, but it doesn't become manifest in only a few generations. This is all nurture, not nature.
Notes Olga Khazan, "The average European man became about 11 centimeters taller between 1870 and 1970, gaining about a centimeter per decade. A mid-19th century British man stood just five feet, four inches tall, but he was five-foot-eight by 1980."
So I urge everybody to read this article. The upshot: lack of disease and better nutrition, especially in the early years, make children taller. Fewer children/smaller families mean less disease in families; hence smaller families in the West has led to taller children as well. Literate parents and cleaner cities also increase average height.
This may be especially interesting to Americans:
For centuries, Americans were the NBA players of the world. We were two inches taller than the Red Coats we squared off against in the American Revolution. In 1850, Americans had about two and a half inches on people from every European country. But our stature plateaued after World War II, and since then, other countries shot past us. White Americans have grown a bit taller since the early 1980s, but African Americans haven’t.
Today Danes, Germans and Norwegians are all taller than us. Why? Better health care and nutrition than in the U.S. Of course, immigrants are most probably bringing down our average, as this year's visit to my local Latin Festival showed me.
By Olga Khazan
May 9, 2014 | The Atlantic