Colorado “Incest” & “Aggravated Incest” Laws (18-6-301 & 18-6-302 C.R.S.)

Colorado’s incest laws prohibit sexual assault or sexual contact with your own child or a blood relative. Colorado’s incest laws also prohibit consensual sex or marriage with step-children and children by adoption – even if you are both adults.

While most of the time the laws prohibiting incest make sense, these provisions can lead to grossly unfair and sometimes bizarre results – including the possibility of life in prison for an affair between consenting grown-ups.

In Colorado, incest and aggravated incest are frequently charged along with sexual assault or sexual assault on a child by one in a position of trust. As a result, charges of incest should be fought vigorously and by the best Colorado sex crimes lawyer you can find.

To help you better understand the complexities of the state’s incest laws, our Denver Colorado criminal defense lawyers discuss the following:

• 1. What is the legal definition of aggravated incest in Colorado?
• 2. What are the consequences of incest?
• 3. What are defenses to Colorado incest / aggravated incest?

Siblings who have sex violate CRS 18-6-301.

1. What is the legal definition of aggravated incest in Colorado?

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 in Colorado

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. What are the consequences of incest?

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.

If, however, the victim suffered bodily injury or you used, possessed, or threatened the use of a deadly weapon, incest can be charged as a Colorado “crime of violence.”

When incest is a crime of violence the minimum sentence increases to more than 10 years in prison.⁴

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.

However, if you caused bodily injury to the victim, or used, possessed or threatened the use of a deadly weapon, aggravated incest can be charged as a Colorado “crime of violence.”

As a crime of violence, the minimum prison time for aggravated incest is 21 years.⁵

Incest is a felony in Colorado.

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:
  1. The victim was under 12 years of age, and
  2. You were at least 18 years old, and
  3. You were at least 10 years older than the victim.

If you fall into one of these categories, you are facing decades in prison. We invite you to contact us to for more information on the sentencing ranges for these specific circumstances.⁶

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.

A violation of any one of these and other conditions is grounds for sending you to prison.

For more information on SOISP, please see the State of Colorado Judicial Department’s Additional Conditions of Probation for Adult Sex Offenders.⁷

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.⁸

3. What are defenses to Colorado incest / aggravated incest?

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:

1. The alleged victim is not a blood relative, an adopted child or a step-child,
2. You did not know the alleged victim was related to you,
3. You did not engage in any prohibited sexual contact or activity with the alleged victim,
4. You and the alleged victim were already married in another state, or
5. The police engaged in illegal conduct in order to entrap you.

In addition, there may defenses unique to your case that have not yet been tested in court, particularly if both you and the child or relative are consenting adults.

Colorado Legal Defense Group
4047 Tejon Street
Denver, CO 80211
(303) 222-0330

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