The Islamic Ruling on Watta Satta (Exchange Marriages)

The concept of Watta Satta is that families marry among themselves, where two siblings from one family are married to two siblings from another family. This creates pressure on both sides; if one sister's marriage fails, the other's won't survive either. Essentially, they agree that 'whatever Mahr is being set, you don't have to pay it.' This is fundamentally a sin because it constitutes Shighar, which is forbidden. Haq Mahr (the dower) is the wife's right; everything else is secondary. Nikah, by definition, is meant to extend your family into other communities and nations. When you marry among good, righteous people [outside the family], it brings special qualities to the offspring. Even science says that [inbreeding allows] recessive genes to become more dominant/harmful, whereas a person grows better in fresh environments and among diverse people.