If you think that kids are now shorter or taller than how your generation used to be, read this:
In 1875, Galton (Google Him) distributed packets of sweet pea pods of uniform size and weight to seven friends. Galton then measured the seeds of the successive generation. He noticed that the median diameter of the large seeds was less than that of the parents while the median diameter of the small seeds were greater that of the parents.
He continued to notice the same effect in the height of humans that is if one’s measurement is far from its mean, the other will closer to its mean “regression toward the mean”. The process doesn’t go out of control. People don’t get dumber or smarter over short periods of time. And the same can be applied to intelligence, artistic talent, etc.
So for example, if the parents are tall, their kids would not necessarily be as tall and if the parents are short, their kids would not be necessarily as short.
Source: Book: The Drunkard's Walk: How Randomness Rules Our Lives by Leonard Mlodinow