Taking up the challenge

Macarena asked the question, "How did inbreeding become a low-class stereotype, when it's the reason Western royal families still exist?" Well, I've taken up the challenge of explaining just that.

Inbreeding of royal lines was the bane of various houses (the Habsburgs and Hanover clans being among the worst) but was not entirely the norm until later centuries.

One example is the Russian Romanov line. The Russians avoided inbreeding up until the late nineteenth/early twentieth centuries with their willingness to A) Marry outside their blood (largely the Germans), and B) The fact that the royal line really wasn't unbroken (Catherine was not a Romanov and God only knows who was the father of her child).

The Habsburgs only intermarried because they wanted to strengthen their control over the various lands in their burgeoning empire.

There were so many royal houses and noblemen/ladies that inbreeding never truly became a threat to their majesties until the lines began to dwindle (noticeably in Britain after the Hundred Years War and across Europe following the plague, Thirty Years War, various revolutions throughout the nineteenth century, etc.).

It was only during the nineteenth century, when royal stock was at an all time ebb due to states uniting from a loose patchwork of nations across Europe into a handful of large empires, that the main houses largely intermarried (Romanov, Hohenzollern, and Hanover/Windsor) to create or tighten alliances only to lead to a variety of odd traits (Kaiser Wilhelm's shrunken, paralyzed arm, the Tsarevich's hemophilia, etc.).

But who else were they to marry? Nobility was waning due to bankruptcy (industrialization led to the creation of a middle class of businessmen, this new style of economy largely dooming the agrarian noble gentry) and being stripped of power through revolutionary upheavals.

The industrial age brought mobility as the peasants fled to the cities leading to the lower classes finally breeding outside their closed towns creating a much more virile stock, a growth in education among the poor and common, and monetary gain leading to an increased voice in government. The entire system found itself turned upside down as the new predominant force, the commoner, came to view the former force, the nobility, as closed, venal, and flagging (which it was by this time). It was the industrial age leading to our modern one that largely removed interbreeding from the common man but induced inbreeding among the shrinking nobility as they banded together against a world threatening to extinguish them.

So as to your point that royal houses got away with inbreeding, they did at times but that was not the norm. They stuck with their own kind. That still happens in our own present time between the classes.

Overall, intermarriage wasn't exactly a lasting or common practice since it led to the extinction of royal houses. Only shortsighted royals and a dwindling royal stock (blame the various revolutions, wars, and more for the shrinking pool of spouses) led to the eventual inbreeding that further doomed an outdated system. These days most royal houses are now open to commoners marrying into royal lines.

As to how inbreeding became a low-class stereotype, if you were to go to Medieval to eighteenth century Europe you'd see few individuals ever managed to leave their towns thus condemning them to interbreed in a very shallow gene pool. So a lack of education mingled with the gradual retarding of stock could only lead to disdain by the upper classes for the lower ones, especially since it was more pronounced and had been going on longer among the lower classes than among the upper classes.

By the by, when the royals interbred it was out of necessity (lack of viable mates). When the lower classes got frisky family style it was by choice since they could marry/breed with anyone.

A rambling defense of royalty from a fiery republican (not the party but of the idea of rule solely by the people). I love to play Devil's advocate.