Inbreeding Can Do More Damage to The Human Body than You Know

A Wild Range of Medical Conditions A study undertaken in France and published in 1977 found that sufferers of cystic fibrosis were more likely to have had parents who were blood relatives, such as cousins. Whereas 0.2% of the population of the country were the result of first-cousin intercourse, the figure was found to be 1.4% for those with cystic fibrosis.