karr-1 said:
Didn't people get taller and bigger in general in the last few hundred years? Maybe "that" did grow as well, who knows.
The growth trend over the last 150 years is known as the "secular trend".
Misleadingly, we are not getting taller at all - only returning to a height that humans have always been. Apparently, the Industrial Revolution was brutal on human health and caused a massive reduction in human height during the 18th and early 19th century (Dickens described is world rather well).
Fact is, prior to the industrial revolution, 6' males were quite common. By 1810, 6' males were very, very rare. They are quite common now again.
And it is to be noted that "Turkana Boy" (the second most famous fossil skeleton) which is some 3.5 million years old projects an adult height of 6'.
So humans are not really growing taller at all. They are only returning to our 'normal' height that was 'stunted' during the industrial revolution (really bad hygene, really bad nutrician, really bad work environments and lots of child labour in mines and mills).
As for statistics on penis size throughout the 20th century, it would appear that studies are increasingly over time suggesting a smaller average size. That is to say, the older 20th century studies suggest a larger average size (cf. Kinsey with 6") and most contemporary studies suggesting 5.5" or even 5" is the average. This evidence suggests almost the contrary to the suggestion of this thread.