Teacher training in computational thinking is becoming more and more important, as many countries are introducing it at all K-12 school levels. Introductory programming courses are known to be difficult and some studies suggest they foster a fixed-mindset views of intelligence, reinforcing the idea that only some people have the so called "geek gene". This is particularly dangerous if thought by future school teachers. Interventions to stimulate "CS growth mindset" in students and their teachers are fundamental and worth CS education research.