In addition to what David just wrote, the Times-Life 1970's series of books on WWII has one volume on the USA Home Front, which is by far my favorite of all those books on the Second World War. One chapter is devoted to building a wartime army in America and the problems facing military officials. It was not the slam dunk, draft 'em and send 'em off to war that most people believe. Eventually, 16,000,000 American men and women served in the American armed forces during the war, but it wasn't easy getting to that figure - mostly because of the after-effects of the Great Depression.
When so many men failed the physical exam early in the war (before women started entering the service in great numbers), FDR was horrified. He commissioned an investigation to find out why this was so. It turns out that the majority of rejections were because of missing teeth, short stature, underweight, poor eyesight, jittery nerves (generally 4-F's) and illiteracy. The reason for each is fairly obvious to us today, given that nutrition during from the second year of the Great Depression through the early 1940's was extremely poor and of insufficient quantity at any rate. People didn't have money to see doctors when diseases or afflictions struck, so many children grew up with lingering effects that stunted their growth and over-all health. This included teeth, eyesight and short stature. The high illiteracy rate was ascribed to children not attending school on a regular basis due to the need to stay at home and work on the farms or because their families were constantly moving, looking for greener grass - which they rarely found.
In 1944, the rejection rate among draftees was so high, that the standards were set to rock bottom, just to replace losses on two war fronts. The army set up schools to bring the 500,000 functionally illiterate soldiers up to a 4th grade reading level. Other accommodations were made for poor or missing teeth and poor eyesight.
Well, you get the picture. The Great Depression's effect on children growing up during those years created a serious problem when it came time to put those young adults into uniform. The Great Depression wasn't just about not having extra spending money or a steady job. It had a lasting effect on at least one generation, the Greatest Generation according to Peter Jennings. I believe he was right.
Marshall