Habsburg Inbreeding & Maria Antonia

The highest coefficient of inbreeding among the Habsburg dynasty was 0.3053, and it belonged to Maria Antonia of Austria. Her coefficient was higher than that of a child born to a parent and child or brother and sister. Her father was her mother's maternal uncle, and her paternal first cousin, once removed, and her maternal grandparents were related as uncle and niece. Remarkably, she was also the niece of Charles II of Spain, one of history's most infamous examples of inbreeding. Interestingly, despite her even higher degree of inbreeding, she did not encounter the same health issues that plagued Charles II.