The twinborn brothers usually combat mutually; on the other hand, pigeon pair has the tendency to incest, with related c孪生兄弟之间往往相互争斗；异性孪生子间则存在乱伦的倾向，而这与两性人有着密切的联系。
Primary Examination on Relativity about the Polymorphism in Blood Protein and Twinborn Ability of Duolang Sheep多浪羊血液蛋白多态性与双羔性能的相关性初探