What are seborrheic keratosis? why do people get them? can they be stopped?

Benign skin growths: Seborrheic keratosis (sks) are common, benign (non-cancerous) tumors of the skin cells. They usually develop in adults over 50 and appear as stuck on, scaly, warts. (google image search will give you some examples). The cause of sks are not exactly known though they tend to run in some families suggesting genetics may partly play a role. There is no way to prevent them.

Seborrheic keratosis: A seborrheic keratosis usually appears as a brown, black or pale growth on the face, chest, shoulders or back. The growth has a waxy, scaly, slightly elevated appearance. Occasionally, it appears singly, but multiple growths are more common. Seborrheic keratoses don't become cancerous, but they can look like skin cancer. They are genetic so you can not stop them.