(a) A person commits incest if the person, being sixteen (16) years of age or older, purports to marry, has sexual intercourse with, or engages in deviate sexual activity with another person sixteen (16) years of age or older whom the actor knows to be:
(1) An ancestor or a descendant;
(2) A stepchild or adopted child;
(3) A brother or sister of the whole or half blood;
(4) An uncle, aunt, nephew, or niece; or
(5) A stepgrandchild or adopted grandchild.
(b) A relationship referred to in this section includes a blood relationship without regard to legitimacy.
(c) Incest is a Class C felony.