(a) Whether or not specifically stated, it is an element of every offense defined in this article, with the exception of subdivision (a)(3) of Section 13A-6-65, that the sexual act was committed without consent of the victim.
(b) Lack of consent results from:
(1) Forcible compulsion; or
(2) Incapacity to consent; or
(3) If the offense charged is sexual abuse, any circumstances, in addition to forcible compulsion or incapacity to consent, in which the victim does not expressly or impliedly acquiesce in the actor's conduct.
(c) A person is deemed incapable of consent if he is:
(1) Less than 16 years old; or
(2) Mentally defective; or
(3) Mentally incapacitated; or
(4) Physically helpless.