From the widest social perspective, or that of the development of the human race, individuals with certain characteristics may be considered unfit to survive, whether because of the disproportionate amount of resources required to care for them or because of genetically determined mental and physical defects which are undesirable in that development. This perspective raises the controversial question of the criteria of fitness for survival and by which it should be determined when the chronically or incurably ill should be allowed to die. This leads onto the equally controversial issues of the conditions of the elimination of those beyond hope and of the sterilization of the unfit to prevent them from perpetuating their defects.
The natural eliminative process has been subverted by genetic tampering and advances in remedial techniques. Foetuses and infants which would otherwise not survive can now be maintained alive despite their defects. The following categories of people may be considered unfit: the mentally unfit (the insane, psychotics, the feeble-minded, the grossly subnormal) and the criminally insane; epileptics; those in prolonged and irreversible coma; those with severe brain damage; those in the terminal phases of illnesses (syphilis, leprosy, tuberculosis, chronic renal and heart disease, multiple sclerosis, etc); the highly deformed (tetraplegia or paraplegia; grossly deformed neonates); those with irremediable behaviour defects (psychopaths, sociopaths incorrigible delinquents; repeated sex offenders; and criminals convicted for capital offences). Other categories might include: chronic substance abusers (drug addicts, alcoholics); and the very senile.