Incest is either moral or immoral in human's perception

According to biology , different species mate  each other  to produce offsprings -that keep them from extinction.  This concept is definitely true to human. Ancient Egyptians exhorted their kings to marry his relative even his own daughters , in order to secure royal monarchy. As human becomes smarter, this idea is construed as a crime because Ancient Greek inveighed against it strongly by creating plays : one of them is Oedipus the king. They begun to question their prior thought , and some of them event surmise that their religion's idea is bombastic. Remember philosophy's goal is to ameliorate life. Even though immorality of incest is permeate , some cultures infringes it; perhaps people's point of view is provincial. Consider this: if incest is so hackneyed why do people keep debating about it? In modern world, many people have observed a  lot of epitome of incest. That renders their emotion lurid. This is really difficult to determine whether or not it is moral.