Great question! In my opinion anyone can do anything as long as they have the qualifications, take John for example. Let’s say he is a random guy from New York with no genetics in the police department. If john takes the tests and training and qualifies as a police man, it shouldn’t matter what his genetics are. I think testing however is a good idea due to the fact it narrows down the participants who in theory should be good at it etc. And separates the strong from the weak. Hope this helps!