To make us more unique, but let me find the actual answer for you.
Moles originate from pigmented cells called melanocytes. Almost everyone has moles, at least a couple. Moles usually develop in childhood or in the teen years of life although some people keep getting moles during their entire lifetime and a few people are born with them. Moles are usually brown in color (due to the melanin pigment) and are a variety of sizes and shapes, can be flat or raised from the skin, and can even contain body hairs. Moles may darken when pregnant, exposed to sunlight, or when undergoing certain medical treatments. It is now thought that many moles develop due to sun exposure (but certainly not all).