One of the first Gumuz cultural practices that I learned about was sister exchange marriage. Despite seeing the challenges that Sudanese face in getting a bride, this practice seemed to trump them all. In most cases, Sudanese brides are "bought" with cows and goats in addition to a new house, clothes and houseware.
But the Gumuz practice a very complex marriage custom which requires that two men from different clans are willing to exchange sisters. Ideally both young men have sisters of approximately the same age. Ideally these sisters are also what we would deem marriageable age. (Yet we have seen on numerous occasions when this is not the case and one girl is under 12 years old.) Although the girls are at times given the right to say no, there are many times when they have no choice in the matter and are traded as if they were materials rather than girls of value.
Of course, most practices have a purpose and this one does as well. It "secures" the marriage for if one marriage fails, the other marriage is forced to separate. If one man is unhappy with his bride and beats her or sends her away, his sister will also return home so the relatives put pressure on them to live at peace. It also "secures" a potential peaceful relationship with another clan and pacifies enemies.
But like most things, sin has corrupted a potential good idea into something devastating. When a woman is unable to give birth, she is seen as useless and returned to the family within a few years. If she is returned, the other marriage (which may have already produced several children) is also broken and that wife compelled to returned to her parents as well.
If one wife is beaten by her husband, the other man is required to beat his wife, regardless of whether he is happy with her or not. If and when he refuses to do so, his family will become angry and place increasing pressure on him. Recently, this has happened to one of our Christian staff. Because his sister is unwilling to return to her husband (because she is being beaten) and because he is unwilling to beat his own wife, he is no longer allowed to live with her. It seems as though there is no way for him to continue living with his wife if his sister refuses to return to her husband.
This sister exchange marriage sounds "simple" until one asks: What if a woman births only boys and there are no sisters to exchange? Then wives must be "purchased" for 10 cows, numerous goats and other items. This becomes so costly that some men must wait many years. A woman might birth only girls in which case, they must wait for a potential suiter willing to buy them.
A woman might birth girls first and then some boys at the end in which case the girls must wait until their brothers grow up before they can wed. I have a dear friend who has already "promised" her 5 year old son to a family who will take him for their 8 year old daughter. This allowed my friend's 18 year old daughter to marry the older brother of the other family. Sound confusing? It is.
Then polygamy enters the picture. Consider, for instance, a family with one boy with 4 sisters. He is able to trade each one of his sisters for a bride allowing him to have 4 wives without payment. If he refuses to do this, his sisters will have to wait until a man is willing to purchase them.
I don't claim to understand it fully but there are pressures and difficult decisions that believers need to make as they find themselves in situations they have no control over. What if their wife does not produce children? Will they go against their culture and keep her? What if they have unmarried sisters? Will they take a second wife in order to allow her to be married? What if their wife is taken back against their will? Pray that believers would have wisdom and that God would intercede on their behalf.