As geneticists would like you to think, perhaps the mother had the "bad mother" gene that caused her pups to be stressful, and then it was passed from generation to generation; it's all determined by genetics.
유전학자들은 어미에게 "나쁜 엄마 유전자"가 있어서 새끼들이 스트레스 받게 하고 대를 거듭하여 그것이 유전되었다고 설명하고 싶어할 것입니다. 모두 유전자가 결정한다는 겁니다.