I got an interesting idea during one of the conversations the other day.
Some people might be empathic, to a larger degree, due to the mental health issues of their parents.
In particular, based on this hypothesis, if parents are unstable in or uncertain about the way they express their emotions or attitude regarding the world surrounding them, then their children are struggling to foresee how their own actions would be judged. Even the smallest misbehavior might be punished hard today, while tomorrow the very same action might be, on the contrary, highly encouraged, following the current mood of an uncertain parent. So, children are often confused and, hence, are forced to adapt to that kind of a situation by putting extra effort to identify current mood of their educators to simply not get in trouble again. This, in turn, get them really trained in being empathic to every person they interact with.