A child inherits blue eyes from both parents, who each carry the recessive blue eye allele.

A person with no known family history suddenly develops type 1 diabetes, an autoimmune condition, later in life.

A person with a family history of cardiovascular disease develops hypertension due to a poor diet and a lack of exercise.

A child inherits cystic fibrosis from both parents who are carriers of the recessive cystic fibrosis gene mutation.