Clearly, roof stains are serious business. 

As Dr. Victor Morgenroth explains in the following article, roof stains, roof mold, fungus, algae, lichens, fungi, moss, and mildew can lead to mold growth which can cause health problems. 

The following examination of roof stains and their potential effects on health was written   by Dr. Victor H. Morgenroth

Dr. Morgenroth is a Keys Gate resident who is a semi-retired, adjunct professor of neurology at UM. He was a principal administrator in the Environment Health and Safety Division of the Organization for Economic Cooperation and Development (OECD) for 20 years; prior to that he was a Group Leader in the Toxicology Division at the Center for Food Saf...