###Human: My son has a small epidermal nevus. Should I worry about potential gene mutation? ###Assistant: Hello. A solitary epidermal nevus is very common and does not pose any kind of serious health concern. Neither is a biopsy required. You are right. Any associated symptom should have been present since birth or early childhood in this case. Even if it is passed on to the future generations, it is harmless. A yearly medical examination is more than enough for the nevi in both your kids. Good luck.