I had to have one of mine assessed by an educational psychologist.
In passing we discussed DC's school, he used to work directly for the school.
He said with absolute conviction that a blue collar parent/s were likely to have a child with a much lower IQ and a white collar parent/s a child with a much higher IQ.
It made me wonder how many other professionals in similar fields have similar ideas?
I was very surprised. Surely this is classist and hasn't the 'thinking' behind IQ evolved anyway?