Section 90 of the Indian Penal Code defines consent in a negative form. It, in effect, says that consent is not a true consent if it is given: (i) By a person under fear of injury, or (ii) Under a misconception of the fact and the person obtaining the consent knows or has reason to believe that the consent was given in consequence of such fear of misconception, or (iii) If the consent is given by a person of unsound mind, (iv) Under intoxication, or (v) Under twelve years of age, and who is unable to understand the nature and consequences of that to which he gives his consent.
Act done by consent:
Sections 87 to 89 and S. 91 of the Indian Penal Code deal with cases where consent is a justification to committing a crime.
In the first place, Section 87 lays down that a person who causes injury to another person above eighteen years of age, who has given his consent to suffer the harm by doing an act which is known by the doer to be likely to cause death or grievous hurt, does not commit an offence. A and Z agree to fence with each other for amusement. This agreement implies the consent of each to suffer any harm which in the course of such fencing, may be caused without foul play; and if A, while playing fairly, hurts Z, A commits no offence. The principle of this section is based upon the maxim Volenti non fit injuria, i.e., that to which man consents cannot be considered an injury, for every person is the best judge of his own interest and no man will consent to what he thinks harmful to himself. In the second place, Section 88 lays down that nothing which is not intended to cause death, is an offence by reason of any harm which it may cause, or be intended by the doer to cause, or be known by the doer to be likely to cause, to any person for whose benefit it is done in good faith, and who has given a consent, whether express or implied, to suffer that harm, or to take the risk of that harm.
A, a surgeon knowing that a particular operation is likely to cause the death of Z, who suffers under a painful complaint, but not intending to cause Z’s death, and intending, in good faith, Z’s benefit, performs that operation on Z, with Z’s consent. A has committed no offence. Persons not qualified as medical practitioners cannot, however, claim the benefit of this section as they can hardly satisfy a court that they had undertaken the operation in good faith as defined in Section 52, for good faith means a conscientious belief that they had skill to perform the operation, while the supposition is that they were unskilled and ignorant.
In the third place, Section 89 empowers the guardian of an infant under twelve years or of an insane person to consent to inflict harm on the infant or the insane person provided it is done in good faith and is done for his benefit. No consent, however, can justify intentional causing of death. A, in good faith, for his child’s benefit without his child’s consent, has his child cut for the stone by a surgeon, knowing it to be likely that the operation will cause the child’s death, but not intending to cause the child’s death.
A is protected by the provisions of this section, inasmuch as his object was the cure of the child. In the fourth place, Section 91 does not extend the protection to offences which are offences independently of any harm which they cause, or be intended to cause, or be known likely to cause, to the person giving the consent, or on whose behalf the consent is given. To illustrate, causing miscarriage is an offence (unless it be caused in good faith for the purpose of saving the life of the woman) independently of any harm which it may cause or be intended to cause to the woman. Therefore, it is not an offence “by reason of such harm,” and the consent of the woman or of her guardian to the causing of such miscarriage does not justify the act.