How Interbreeding Turned The Spanish Royals Mad

The history of the Spanish royal family between 1547 and 1759 was one of almost constant misfortune, due to the physical and mental infirmities of many of its members. There were intervals during which sanity was resumed, but these did not last. There was one single root cause, namely the royal custom of marrying within the family so that unfortunate genetic conditions became inherited by later generations. <a href="https://medium.com/illumination/how-interbreeding-turned-the-spanish-royals-mad-50040424c60c">Read More</a>