Another point to be noted is that when a person with a family history of a mental disorder raises a family, only 50% of their genes are transferred to the baby, the rest 50% being the genes of the other partner. This means that genetically, a person having a genetic background of mental illness, like depression, is only under 50% risk of developing the same. It is up to you if you look at it as 'the glass is half empty, or the glass is half full'!