On IQ and genetics.
My maternal Aunt earned a PHD in Chemical Engineering the late 50s/early 60s. My maternal uncle got a PHD in psychology and worked on mainframes while in college in the early 60s. My mom had a degree in English but worked as a field auditor - being very good with numbers as well - and read 3-5 books a week. My maternal grandmother ran a large business with her husband handling sales. Both were dirt poor growing up.
My dad had 100% in all his service schools in the Army and was honor graduate in all. He had 100% on his A&P tests and had 100% availability on all his airframes. He is still extremely sharp.
My DW's dad has a photographic memory. He had the entire parts catalog for all major auto manufacturers memorized. DW has a photographic memory for anything she hears. She has thousands of songs memorized. Before her concussion in her 20s, she had a visual photographic memory and could recall just about anything she had seen. She does have a visual processing problem and cannot read very fast. She can look at columns of numbers and know immediately if something is off. DW is very, very good at videogames. DW's sister is a phenomenal freehand artist.
Two of my sister's four kids have been admitted to GT programs. One, at age 7, was able to beat me at chess after a month of playing - if I did not work to win. Another is very gifted artistically and can draw anything he sees.
So, I think GT is strongly genetic. I also think that it also needs the right environment to flourish. My sister's kids have not had that much opportunity - the oldest was an amazing kid at 6 - but did not get consistent attention - too much TV and not enough books. And the artist has not been around any other artists.
