
1. Aggravated Incest Defined
Incest — 18-6-301 C.R.S.
Any person who knowingly marries, inflicts sexual penetration or sexual intrusion on, or subjects to sexual contact, as defined in section 18-3-401, an ancestor or descendant, including a natural child, child by adoption, or stepchild twenty-one years of age or older, a brother or sister of the whole or half blood, or an uncle, aunt, nephew, or niece of the whole blood commits incest, which is a class 4 felony. For the purpose of this section only, “descendant” includes a child by adoption and a stepchild, but only if the person is not legally married to the child by adoption or the stepchild.1
Aggravated Incest — 18-6-302 C.R.S.
A person commits aggravated incest when he or she knowingly:
(a) Marries his or her natural child or inflicts sexual penetration or sexual intrusion on or subjects to sexual contact, as defined in section 18-3-401, his or her natural child, stepchild, or child by adoption, but this paragraph (a) shall not apply when the person is legally married to the stepchild or child by adoption. For the purpose of this paragraph (a) only, “child” means a person under twenty-one years of age.
(b) Marries, inflicts sexual penetration or sexual intrusion on, or subjects to sexual contact, as defined in section 18-3-401, a descendant, a brother or sister of the whole or half blood, or an uncle, aunt, nephew, or niece of the whole blood who is under ten years of age.2
The difference between incest and aggravated incest
Colorado’s incest law — 18-6-301 C.R.S. – applies to all descendants and close blood relatives, regardless of their age. Colorado’s aggravated incest law — 18-6-302 C.R.S. applies to:- All children (including stepchildren and adopted children) under age 21, and
- Other close blood relatives who are under age 10.3
Example: Donald marries Elizabeth, who has a 14-year old daughter, Kelly. If Donald has sex with Kelly, he is committing aggravated incest (as well as sexual assault under Colorado 18-3-402 C.R.S.). Even if he waits until Kelly turns 17, the legal age of consent in Colorado, Donald is still guilty of aggravated incest. It doesn’t even matter if Donald divorces Elizabeth and wants to marry Kelly. Because Kelly is under age 21 and his step-daughter, the union is prohibited by Colorado’s aggravated incest law. Waiting until Kelly is 21 does not solve the problem, either. It is still prohibited under Colorado’s law (though it can be prosecuted as incest rather than aggravated incest).See our related article, The Difference Between “Incest” and “Aggravated incest” in Colorado.
2. Penalties
Incest penalties
Under 18-6-301 C.R.S., incest is a Colorado class 4 felony. Provided the victim was not bodily injured and you did not use, possess, or threaten the use of a deadly weapon, punishment for incest can include:- An indeterminate sentence of between 2 years and life in prison, and/or
- A fine of $2,000-$500,000.
Aggravated incest penalties
Under 18-6-303 C.R.S., aggravated incest is a Colorado class 3 felony. Punishment for aggravated incest in Colorado can include:- An indeterminate sentence of between 4 years and life in prison, and/or
- A fine of $3,000-$750,000.

Increased sentence for habitual sex offenders, HIV positive offenders, or victim under age 12
The minimum prison sentence you serve will be much, much longer if:- You are a Colorado “habitual sex offender”;
- You knew at the time of the offense you had tested positive for HIV and you infected the victim; or
- The incest included an act of penetration or intrusion and at the time of the offense:
- The victim was under 12 years of age, and
- You were at least 18 years old, and
- You were at least 10 years older than the victim.
Alternatives to prison for Colorado sex offenders
Provided the incest or aggravated incest was not a crime of violence and you are not a Colorado habitual sex offender, the court may, in its discretion:- Defer your sentence and give you the chance to complete counseling and treatment, or
- Sentence you to probation instead of incarceration.
Probation under Colorado’s Sex Offender Intensive Supervised Probation (SOISP)
If you are sentenced to probation, it will last for at least ten years if you were convicted of incest, or twenty years if the crime was aggravated incest. However, you may be on probation for the rest of your life. The terms of your probation will include severe restrictions on where you can go, who you can associate with, and what you can do. Your probation conditions will include:- Participation in Colorado’s Sex Offender Intensive Supervised Probation, or SOISP;
- Participation in an approved sex offender evaluation and treatment program;
- Registration as a Colorado sex offender;
- Genetic marker testing;
- No use of drugs or alcohol;
- No contact with children (even your own);
- No contact with any victim;
- No dating or marriage of anyone with children under 18 unless approved by the state;
- No possession of porn; and
- No change of residence unless approved by the state of Colorado.
Conditions of parole for convicted sex offenders in Colorado
Once you are released from prison, you will be placed on parole. You will be required to wear electronic monitoring for the entire duration of parole. Tampering with the electronic monitoring is a parole violation that could get you sent back to prison.Sex offender registration
If you are convicted of incest or aggravated incest, you will be required to register as a Colorado sex offender. The requirement will remain in place for at least 20 years from the time you are fully released from the court and prison system. 83. Best Defenses
Incest and aggravated incest can be difficult crimes to defend. The best defense to Colorado incest charges usually involves fighting the underlying sexual offense itself. Other defenses may, however, include:- The alleged victim is not a blood relative, an adopted child or a step-child,
- You did not know the alleged victim was related to you,
- You did not engage in any prohibited sexual contact or activity with the alleged victim,
- You and the alleged victim were already married in another state, or
- The police engaged in illegal conduct in order to entrap you.
Legal References
- CRS 18-6-301; see also McGee v. People, (1966) 160 Colo. 46, 413 P.2d 901.
- CRS 18-6-302; see also United States v. Vigil, (10th Cir. 2003) 334 F.3d 1215.
- CRS 18-6-301; CRS 18-6-302.
- CRS 18-6-301.
- CRS 18-6-302.
- CRS 18-3-412; CRS 18-3-415.5.
- CRS 18-1.3-1007.
- CRS 16-22-103.