Researchers who wanted to find out why it is not only taboo to kiss your sister, but also disgusting, said they have discovered why in a discovery that challenges some basic tenets of Freudian theory.

• 想找出为什麽亲吻你的姊妹不只是禁忌而且还很恶心的研究人员说，他们已在一项挑战了部分佛洛伊德理论基本信条的发现中，找出原因。