A couple of people requested that I email them my friend's theory about why the world is getting more and more stupid, but there is no reason not to post it. I am pretty sure he is not going to do studies on this issue. According to my son there is a movie out called "Idiocracy" but I have only seen the first few minutes of it.
My friend theorized that the average IQ (at least in this country) was dropping by leaps and bounds. He said it was because educated people finished high school and went on to actually become educated. Bachelor's Degrees, Master's Degrees, and Doctorates all take time and money and effort to attain and most people who do attain them do not do so with a wife and 10 children following them around (or a husband and 9 children, ha ha!!). Sorry that was sexist.
But, my friend said, some people married fresh out of high school, before they have enough sense to know that the world is not always fair and they start having children immediately. And (on average) uneducated people raise uneducated people. And those who start when they are 18 continue until their child bearing years are over. (And some men continue to have 2nd, 3rd and 4th families!!)
Of course people with advanced degrees normally wait until they are older to marry and to start having children, and then it is possible that there are health concerns that may or may not allow them to have children or which may limit their number.
Now this is obviously a very flimsy theory with absolutely no scientific principles behind it. It was just my friend thinking out loud. There are many, many people who do not fall into this category and I am one of them. I was married at 19 and pregnant at 21 with 1 semester of college behind me. There were no more pregnancies after that. Another of my friends is an M.D., the son of 2 PhDs and he is the oldest of 8 children.
But look around at the poorer neighborhoods, at the children with more than 1 sibling in your child's class. It is definitely possible.
And my ex is currently expecting his 3rd child. He turned 46 today. He has only a high school diploma, although his current wife (who is not yet 30) does have a Bachelor's Degree. But she still married him and she can't figure out how to prevent unwanted children. How high is her IQ?