Informed consent is a phrase often used in law to indicate that the consent a person gives meets certain minimum standards. As a literal matter, in the absence of fraud, it is redundant. An informed consent can be said to have been given based upon a clear appreciation and understanding of the facts, implications, and future consequences of an action. In order to give informed consent, the individual concerned must have adequate reasoning faculties and be in possession of all relevant facts at the time consent is given. Impairments to reasoning and judgment which may make it impossible for someone to give informed consent include such factors as basic intellectual or emotional immaturity, high levels of stress such as PTSD or as severe mental retardation, severe mental illness, intoxication, severe sleep deprivation, Alzheimer's disease, or being in a coma. This term was first used in a 1957 medical malpractice case by Paul G. Gebhard.