(a) A person commits the crime of rape in the second degree if:
(1) Being 16 years old or older, he or she engages in sexual intercourse with a member of the opposite sex less than 16 and more than 12 years old; provided, however, the actor is at least two years older than the member of the opposite sex.
(2) He or she engages in sexual intercourse with a member of the opposite sex who is incapable of consent by reason of being mentally defective.
(b) Rape in the second degree is a Class B felony.