In Frank Herbert’s Dune, the character Lady Jessica is under orders from a powerful group to only bear her husband daughters. Eventually, it is revealed that the purpose of this was to ensure that her daughter could be wed to the son of an enemy clan, in order to seal the rift between them.
While such marriages have a medieval feel, it certainly seems to be the case that such unions can unite differing factions and promote the emergence of new political unions. It will be interesting to see how gay marriage changes that dynamic, especially if it spreads beyond liberal democracies. Such unions will not be able to produce biological children – for the foreseeable future – but perhaps they will still serve the role of binding groups together.
How different Dune would have been if Paul Atreides could have wed Feyd-Rautha or Glossu Rabban.
