survivor guilt: a deep feeling of guilt often experienced by those who have survived some catastrophe that took the lives of many others; derives in part from a feeling that they did not do enough to save the others who perished and in part from feelings of being unworthy relative to those who died
guilt: remorse caused by feeling responsible for some offense
pronucleus: the nucleus of the ovum or sperm after fertilization but before they fuse to form the nucleus of the zygote