Colorado “Incest” & “Aggravated Incest” Laws and Penalties

Colorado incest laws make it a felony to knowingly marry, inflict sexual penetration or sexual intrusion on, or subject to sexual contact certain close relatives. Depending on the relationship and the age of the alleged victim, the charge may be either incest or aggravated incest.

In Colorado, both incest and aggravated incest are treated as sex offenses for sentencing purposes. This means many convictions are subject to Colorado’s indeterminate sentencing scheme, where the judge imposes a minimum term and a maximum of life in prison.

Note that incest and aggravated incest are frequently charged along with sexual assault or sexual assault on a child by one in a position of trust. This means that defendants potentially face multiple life sentences.

In this article, our Colorado criminal defense lawyers will address the following key issues regarding Colorado incest laws:

• 1. Elements
• 2. Penalties
• 3. Defenses
• Frequently Asked Questions
• Additional Resources

1. Elements

For you to be convicted of incest under C.R.S. 18-6-301, Colorado prosecutors have to prove beyond a reasonable doubt that:

1. You knowingly married, inflicted sexual penetration or sexual intrusion on, or subjected to sexual contact a person; and
2. That person was your:
   • ancestor;
   • descendant, including a natural child, child by adoption, or stepchild who is 21 or older;
   • brother or sister of the whole or half blood; or
   • uncle, aunt, nephew, or niece of the whole blood.

For this statute only, “descendant” includes an adopted child or a stepchild, but only if you are not legally married to that adopted child or stepchild.¹

For you to be convicted of aggravated incest under C.R.S. 18-6-302, Colorado prosecutors have to prove beyond a reasonable doubt that you knowingly married, inflicted sexual penetration or sexual intrusion on, or subjected to sexual contact either:

• your natural child, stepchild, or adopted child who is under 21; or
• a descendant, brother, sister, uncle, aunt, nephew, or niece of the whole or half blood who is under 10.

The statute also says aggravated incest does not apply when the person is legally married to the stepchild or adopted child.²

Example: If a man has sexual contact with his 17-year-old stepdaughter, prosecutors could charge aggravated incest because a stepchild under 21 is covered by C.R.S. 18-6-302. It does not matter that 17 is the age of consent in Colorado for many other sex offenses.

See our related article, The Difference Between “Incest” and “Aggravated Incest” in Colorado.

Siblings who have sex can be prosecuted for incest in Colorado.

2. Penalties

Under C.R.S. 18-6-301, incest is a class 4 felony carrying at least two years to life in Colorado State Prison. The court may also impose a fine of $2,000 to $500,000.³

Under C.R.S. 18-6-302, aggravated incest is a class 3 felony carrying at least four years to life in prison. The court may also impose a fine of $3,000 to $750,000.⁴

If the offense qualifies as a crime of violence because it involved threats or bodily injury, the minimum prison term increases.⁵ The minimum prison term can also increase if, for example:

• you qualify as a habitual sex offender against children;
• you had notice that you were HIV-positive before the offense and the virus was transmitted; or
• the offense falls within one of the special sentencing provisions in Colorado’s sex-offender sentencing statutes.⁶

Once you are released from prison, you will be pleased on an intensive supervision parole program. Depending on the case, conditions can include curfews, home visits, employment monitoring, treatment monitoring, and other restrictions designed to protect the public.⁷ Parole may also involve electronic monitoring for the entire parole period.⁸

Probation under Colorado’s Sex Offender Intensive Supervision Probation (SOISP)

In some cases, the judge may grant probation instead of prison. If probation is allowed, it is indeterminate:

• at least 10 years for incest and
• at least 20 years for aggravated incest

up to a maximum of life.⁹

However, probation is not available if the offense is a crime of violence, if you qualify as a habitual sex offender against children, or if you fall under the special sentencing provision in C.R.S. 18-1.3-1004(1)(e).¹⁰

If probation is granted, the court must order you to participate in Colorado’s sex offender intensive supervision probation program (SOISP). Conditions often include:

• sex-offender evaluation and treatment;
• registration as a sex offender;
• close supervision by probation;
• limits on contact with victims or minors;
• curfews, home visits, and employment monitoring;
• drug and alcohol screening; and
• other case-specific restrictions imposed by the court.¹¹

A violation of probation can lead to revocation and prison.

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

Sex Offender Registration

A conviction for either incest or aggravated incest requires sex-offender registration in Colorado.¹² For adult convictions, both incest and aggravated incest require quarterly registration for the remainder of your life.¹³

Failing to register or update registration information is a separate criminal offense.¹⁴

3. Best Defenses

Here at Colorado Legal Defense Group, we have represented literally thousands of people charged with sex crimes such as incest. In our experience, the following defenses can be effective, depending on the facts of the case:

1. The alleged victim does not fall within the relationship described by the statute.
2. You did not knowingly engage in the prohibited conduct.
3. No sexual contact, sexual intrusion, sexual penetration, or marriage occurred.
4. The prosecution cannot prove the age element required for aggravated incest.
5. A statement, search, or seizure by police was unlawful and should be suppressed.

Incest is a felony in Colorado.

Legal References