Circumstantial evidence exists that acne is in part a genetic, or inherited, disease. In studies of identical twins twins that develop from one fertilized egg if one twin had acne, 97 percent of the other co-twins had acne as well.

In the case of no identical twins or twins that develop from separate fertilized eggs the figure was 50 percent. In other family studies, 80 percent of acne sufferers had a brother or sister similarly afflicted, and in 60 percent one or both parents had experienced acne while growing up.

There is an impression among dermatologists that the most severe cases of acne occur in those youngsters both whose parents had acne or where one parent had very severe acne.

What does all this mean?

It simply suggests that some unknown trait or factor can be passed on from parent to that, in the presence of other existing factors, promotes the development of acne.