Researchers have discovered a genetic variation that may contribute to how empathetic a human is, and how that person reacts to stress. In the first study of its kind, a variation in the hormone/neurotransmitter oxytocin's receptor was linked to a person's ability to infer the mental state of others.
Hmmmmm, can't help but wonder what sort of birth and early upbringing the folks with the gene variation had. The environment has a huge impact on which genes get switched on which ones get switched off. How the genes get tinkered with and altered too depends upon the environment. Epigenetics is the field of science exploring genetic behaviour in response to environmental cues. The issue of the early environment on the person's oxytocin's receptor variation would be good study.
Study links genetic variation to individual empathy, stress levels