My Wife does not want my Son learning coding. She wants him to become a doctor. My Son is 4 years old and he's quite fascinated with games and my ipad. I feel I should overrule her and send him for classes. How can I convince my Wife?

Tell her coding lessons does not just mean that your son will go into that particular profession. Coding will help develop other skills like logic, attention to detail etc. All these skills can easily be transferred to other activities and future professions -- such as a doctor. At the end of the day, it's not really your choice issit? It's your child's choice so why not just expose him to anything that could give him a heads start in life :)