We may inherit many things from our family such as heirlooms and how we look; and sometimes we may inherit trauma. It is estimated that we have more than 25,000 genes in our DNA. Some lie dormant and some can activate based on our environment. The way our genes determine our physical characteristics and even which diseases we may be predisposed to is called epigenetics - the study of inheritable changes in gene function; how behaviors, events, and environment change the way our genes are expressed.