Small Bald Spots Developing On Two Cousins — Is this Heredity or Is the Barber Spreading It?

I’m a barber, and one of my clients (male 27) is developing small bald spots all over his head. The hair is not completely gone, but it is very thin and slightly lighter then the rest of the hair. I think its alopecia, but his cousin (male 28) is developing the same thing. He comes to the same shop as well however the other barber cuts his hair. My question is could this be something that I’m passing to my clients, or is this heredity?

I am not sure what you are describing. Ringworm, head lice, or other contagious skin problems can be spread in a barber shop or in a household. I would need to see them to make a diagnosis.