I could agree with attractivness / ugliness or strenght / weakness, but other genetic traits should be very rare and hard to pass to next generations in my opinion. In vanilla its to easy to create whole army of genetic super humans, making traits like genius or quick to stick to every heir in every generation. Thats why I like CK2+, where you cant just find loads of genius spouses every year, they happen to appear as some unique anomaly and thats how it should be imo. Even in CK2+ usually there is at least one lucky child that gets some genetic trait from his / her father / mother in every ruling family, especially in case of those trully genetic traits - strong, weak, attractive, ugly. Im not sure if genius or quick trait should be even considered as a genetic trait - its not like geniuses consequently breed geniuses, I think its rather a random thing, and vanilla makes them totally overpowered and illogical. But thanks to that, when u happen to become a genius or quick ruler then your are twice more happy than normally in vanilla