Polyandry is the state or condition of one woman having two or more husbands simultaneously. Polyandry is rare, though it is found among the Shoshone of Nevada, the Todas in India, the Bashile of the Congo, and the Yanomanis in Venezuela. Although the Bible includes numerous examples of men having multiple wives, nowhere in the Bible do we find an example of polyandry, the state of one woman being married to more than one man. Because of this, many, even those who allow for polygamy, have concluded that polyandry is a sin today.
What Did Aquinas Say About Polyandry?
According to Saint Thomas Aquinas, it is critical for a child's self-identity to know who his biological parents are. Therefore, according to Aquinas, the practice of polyandry is unthinkable as "man naturally desires to know his offspring, and this knowledge would be completely destroyed if there were several males for one female. Therefore, that one female is for one male is a consequence of natural instinct." (Summa Contra Gentiles III. 124.1)
In the practice of polyandry there is no certainty of family relations as the woman has sexual relations with numerous men. Simply put, according to Aquinas, polygamy does not directly conflict with natural law because in it the child knows who his parents are. Aquinas believed that polyandry conflicts with natural law.
I have to agree with Aquinas... to an extent. But what if there is no desire to produce children? And what if safe and effective birth control is implemented? After all, the pill and condom were invented long after Aquinas was picking daisies; certainly, this added ingredient should be a relevant consideration when evaluating this ethical equation.
Furthermore, isn't becoming one flesh just as much a purpose for sex as producing babies? And pardon me for sounding a bit hedonistic, but is it really such a bad thing to enjoy sex for no other reason than just... enjoying sex?
However, there are other matters to consider in regards to polyandry. For example, in most cultures, there are more men than women. However, this has not always been the case. For example, female infanticide, i.e. the slaying of female babies, was common in some traditional patriarchal societies, such as ancient Greece and Rome. It is also becoming increasingly common today in parts of India and China. According to a web article entitled Indian Organizations Struggle to Remedy Frightening Sex Ratio:
NEW DELHI, Sept 9 (OneWorld South Asia) - It is believed that the Chinese kill over a million girls every year in order to have a boy. It is also believed that Indians are about to overtake the Chinese in a few years. With an alarmingly adverse sex ratio of 933 women per thousand men, which is the lowest in south Asia, Indians have gained notoriety for selectively killing female fetuses.In Greece and ancient Rome, a child was virtually its father's chattel—e.g., in Roman law, the Patria Potestas granted the father the right to dispose of his offspring as he saw fit. In Sparta the decision was made by a public official. Child sacrifice occurs in many traditional societies for religious reasons, but human sacrificial victims were generally appreciated members of society, unlike victims of infanticide, who were devalued.