(a) A person commits the offense of incest when the person engages in sexual intercourse with a person to whom he or she knows he or she is related either by blood or by marriage as follows:
(1) Father and daughter or stepdaughter;
(2) Mother and son or stepson;
(3) Brother and sister of the whole blood or of the half blood;
(4) Grandparent and grandchild;
(5) Aunt and nephew; or
(6) Uncle and niece.
(b) A person convicted of the offense of incest shall be punished by imprisonment for not less than ten nor more than 30 years; provided, however, that any person convicted of the offense of incest under this subsection with a child under the age of 14 years shall be punished by imprisonment for not less than 25 nor more than 50 years. Any person convicted under this Code section of the offense of incest shall, in addition, be subject to the sentencing and punishment provisions of Code Section 17-10-6.2.