Pennsylvania Statutes Title 18 Pa.C.S.A. Crimes and Offenses § 4302. Incest

(a) General rule.--Except as provided under subsection (b), a person is guilty of incest, a felony of the second degree, if that person knowingly marries or cohabits or has sexual intercourse with an ancestor or descendant, a brother or sister of the whole or half blood or an uncle, aunt, nephew or niece of the whole blood.

(b) Incest of a minor.--A person is guilty of incest of a minor, a felony of the second degree, if that person knowingly marries, cohabits with or has sexual intercourse with a complainant who is an ancestor or descendant, a brother or sister of the whole or half blood or an uncle, aunt, nephew or niece of the whole blood and:

(c) Relationships.--The relationships referred to in this section include blood relationships without regard to legitimacy, and relationship of parent and child by adoption.