Wash. Rev. Code » Title 9A · Chapter 9A.64
Revised Code of Washington

Wash. Rev. Code § 9A.64.020 (2026)

Incest

✓ current as of May 2026
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(1)(a) A person is guilty of incest in the first degree if he or she engages in sexual intercourse with a person whom he or she knows to be related to him or her, either legitimately or illegitimately, as an ancestor, descendant, brother, or sister of either the whole or the half blood.
(b) Incest in the first degree is a class B felony.
(2)(a) A person is guilty of incest in the second degree if he or she engages in sexual contact with a person whom he or she knows to be related to him or her, either legitimately or illegitimately, as an ancestor, descendant, brother, or sister of either the whole or the half blood.
(b) Incest in the second degree is a class C felony.
(3) As used in this section:
(a) "Descendant" includes stepchildren and adopted children under eighteen years of age;
(b) "Sexual contact" has the same meaning as in RCW 9A.44.010; and
(c) "Sexual intercourse" has the same meaning as in RCW 9A.44.010.
[ 2003 c 53 s 80; 1999 c 143 s 39; 1985 c 53 s 1; 1982 c 129 s 3; 1975 1st ex.s. c 260 s 9A.64.020.]

Notes:

Intent—Effective date—2003 c 53: See notes following RCW 2.48.180.
Severability—1982 c 129: See note following RCW 9A.04.080.
Notes of Decisions
Cited in 86 cases (12 in the last 5 years), 1980–2026 · leading case: State Of Washington, V. Ian Anthony Gantt, 540 P.3d 845 (Wash. Ct. App. 2024).
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State Of Washington, V. Ian Anthony Gantt, 540 P.3d 845 (Wash. Ct. App. 2024). · cites it 13× “Gantt appeals his conviction on numerous grounds, including that RCW 9A.64.020, criminalizing incest, is facially unconstitutional.”
State v. Chenoweth, 370 P.3d 6 (Wash. 2016). · cites it 4× “’’), ,030(47)(a)(ii) (“sex offense’’ includes a violation of RCW 9A.64.020 (defining incest)), .515 (indicating RCW 9A.”
Pers. Restraint Petition of Eddie Dean Arnold, 396 P.3d 375 (Wash. Ct. App. 2017). · cites it 6× “100 (1975) (indecent liberties); former RCW 9A.64.020 (1975) (incest). 5 See former RCW 9.”
State v. Calle, 888 P.2d 155 (Wash. 1995). · cites it 2× “1 "RCW 9A.64.020 Incest. (1) A person is guilty of incest in the first degree if he engages in sexual intercourse with a person whom he knows to be related to him, either legitimately or illegitimately, as an ancestor, descendant, brother, or sister of either the whole or the…”
Commonwealth v. Rahim, 805 N.E.2d 13 (Mass. 2004). · cites it 3× “1 (Michie 1998) (punishing as incest sexual contact “if the other person is under the age of twenty-one and is within the degree of consanguinity or affinity within which marriages are by the laws of this state declared void”); Wash. Rev. Code § 9A.64.020 (2002) (punishing as…”
State v. Arseneau, 879 P.2d 1003 (Wash. Ct. App. 1994). · cites it 14× “RCW 9A.64.020 does not criminalize sexual relations with a stepchild unless that child is under 18 years of age.”
State v. Smith, 610 P.2d 869 (Wash. 1980). · cites it 2× “010; incest, RCW 9A.64.020. I find it grossly disproportionate to include the mere possession of over 40 grams of marijuana in the same category as the crimes cataloged above.”
State v. Chenoweth, 354 P.3d 13 (Wash. Ct. App. 2015). · cites it 2× “9 The incest statute under which Chenoweth was charged, RCW 9A.64.020, does not use the term “child.”
State v. Sexsmith, 138 Wash. App. 497 (Wash. Ct. App. 2007). · cites it 2× “Former RCW 9A.64.020(1) (1989). The term “descendant” includes stepchildren younger than 18 years of age.”
State v. Sexsmith, 157 P.3d 901 (Wash. Ct. App. 2007). · cites it 2× “Former RCW 9A.64.020(1) (1989). The term "descendant" includes stepchildren younger than 18 years of age.”
In re Pers. Restraint of Arnold, 410 P.3d 1133 (Wash. 2018). “132 ; (ii) A violation of RCW 9A.64.020 ; (iii) A felony that is a violation of chapter 9.”
State v. Osman, 139 P.3d 334 (Wash. 2006). “FACTS AND PROCEDURAL HISTORY ¶ 2 In November 2003, Osman pleaded guilty to three counts of incest in the second degree under RCW 9A.64.020(2). [1] Osman was eligible for [2] and requested a SSOSA.”
Show all 86 citing cases →
— Wash. Rev. Code § 9A.64.020(1) — 15 cases
State v. Chenoweth, 370 P.3d 6 (Wash. 2016). “’’), ,030(47)(a)(ii) (“sex offense’’ includes a violation of RCW 9A.64.020 (defining incest)), .515 (indicating RCW 9A.”
State v. Calle, 888 P.2d 155 (Wash. 1995). “1 "RCW 9A.64.020 Incest. (1) A person is guilty of incest in the first degree if he engages in sexual intercourse with a person whom he knows to be related to him, either legitimately or illegitimately, as an ancestor, descendant, brother, or sister of either the whole or the…”
State v. Bobenhouse, 166 Wash. 2d 881 (Wash. 2009).
State v. Sexsmith, 138 Wash. App. 497 (Wash. Ct. App. 2007). “Former RCW 9A.64.020(1) (1989). The term “descendant” includes stepchildren younger than 18 years of age.”
State v. Sexsmith, 157 P.3d 901 (Wash. Ct. App. 2007). “Former RCW 9A.64.020(1) (1989). The term "descendant" includes stepchildren younger than 18 years of age.”
— Wash. Rev. Code § 9A.64.020(1)(a) — 10 cases
State Of Washington, V. Ian Anthony Gantt, 540 P.3d 845 (Wash. Ct. App. 2024). “Gantt appeals his conviction on numerous grounds, including that RCW 9A.64.020, criminalizing incest, is facially unconstitutional.”
In Re Det. of Boynton, 216 P.3d 1089 (Wash. Ct. App. 2009).
State Of Washington, V. Harlan W. Blackburn (Wash. Ct. App. 2026).
State Of Washington, V John K. L. Aylward (Wash. Ct. App. 2018).
State Of Washington v. Richard G. Neighbarger (Wash. Ct. App. 2018).
— Wash. Rev. Code § 9A.64.020(1)(b) — 3 cases
State Of Washington, V. Harlan W. Blackburn (Wash. Ct. App. 2026).
State Of Washington, V Jeffrey L. Butterfield (Wash. Ct. App. 2021).
State Of Washington v. Timothy Allen Ludwig (Wash. Ct. App. 2014).
— Wash. Rev. Code § 9A.64.020(2) — 8 cases
State v. Osman, 139 P.3d 334 (Wash. 2006). “FACTS AND PROCEDURAL HISTORY ¶ 2 In November 2003, Osman pleaded guilty to three counts of incest in the second degree under RCW 9A.64.020(2). [1] Osman was eligible for [2] and requested a SSOSA.”
State v. Hyder, 244 P.3d 454 (Wash. Ct. App. 2011).
State v. Jackson, 711 P.2d 1086 (Wash. Ct. App. 1985).
State v. Osman, 126 Wash. App. 575 (Wash. Ct. App. 2005).
State v. Hyder, 159 Wash. App. 234 (Wash. Ct. App. 2011).
— Wash. Rev. Code § 9A.64.020(2)(a) — 4 cases
State v. Gower, 288 P.3d 665 (Wash. Ct. App. 2012).
State Of Washington, V. Trent Wayne Tyler (Wash. Ct. App. 2022).
State Of Washington, V. Michael S. Adams (Wash. Ct. App. 2025).
State Of Washington, V. Randolph Thomas Mcintyre (Wash. Ct. App. 2025).
— Wash. Rev. Code § 9A.64.020(3) — 6 cases
State v. Sexsmith, 138 Wash. App. 497 (Wash. Ct. App. 2007). “Former RCW 9A.64.020(1) (1989). The term “descendant” includes stepchildren younger than 18 years of age.”
State v. Sexsmith, 157 P.3d 901 (Wash. Ct. App. 2007). “Former RCW 9A.64.020(1) (1989). The term "descendant" includes stepchildren younger than 18 years of age.”
State v. Arseneau, 879 P.2d 1003 (Wash. Ct. App. 1994). “RCW 9A.64.020 does not criminalize sexual relations with a stepchild unless that child is under 18 years of age.”
State v. Collins, 847 P.2d 528 (Wash. Ct. App. 1993).
State v. Hall, 112 Wash. App. 164 (Wash. Ct. App. 2002).
— Wash. Rev. Code § 9A.64.020(3)(a) — 4 cases
State Of Washington, V John K. L. Aylward (Wash. Ct. App. 2018).
State Of Washington, V John Thomas Black (Wash. Ct. App. 2022).
State Of Washington, V. William Leroy Burch, Iii (Wash. Ct. App. 2023).
State Of Washington, V. Gerardo Elicier Monge (Wash. Ct. App. 2025).
— Wash. Rev. Code § 9A.64.020(4) — 1 case
State v. Arseneau, 879 P.2d 1003 (Wash. Ct. App. 1994). “RCW 9A.64.020 does not criminalize sexual relations with a stepchild unless that child is under 18 years of age.”
— Wash. Rev. Code § 9A.64.020(5) — 2 cases
State v. Arseneau, 879 P.2d 1003 (Wash. Ct. App. 1994). “RCW 9A.64.020 does not criminalize sexual relations with a stepchild unless that child is under 18 years of age.”
State v. DR, 930 P.2d 350 (Wash. Ct. App. 1997).
— Wash. Rev. Code § 9A.64.020(S)(a) — 1 case
Bradford v. Commonwealth, 345 S.W.3d 245 (Ky. Ct. App. 2011).
— Wash. Rev. Code § 9A.64.020(l)(a) — 3 cases
Bradford v. Commonwealth, 345 S.W.3d 245 (Ky. Ct. App. 2011).
State v. Gower, 288 P.3d 665 (Wash. Ct. App. 2012).
In re the Det. of Boynton, 152 Wash. App. 442 (Wash. Ct. App. 2009).
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