The following information was taken directly from the Missiouri State Legislation website at http://www.moga.mo.gov/STATUTES/C566.HTM
Chapter 566 and chapter 568 definitions.
566.010. As used in this chapter and chapter 568, RSMo, the following terms mean:
(1) "Deviate sexual intercourse", any act involving the genitals of one person and the hand, mouth, tongue, or anus of another person or a sexual act involving the penetration, however slight, of the male or female sex organ or
the anus by a finger, instrument or object done for the purpose of arousing or gratifying the sexual desire of any person or for the purpose of terrorizing the victim;
(2) "Sexual conduct", sexual intercourse, deviate sexual intercourse or sexual contact;
(3) "Sexual contact", any touching of another person with the genitals or any touching of the genitals or anus of another person, or the breast of a female person, or such touching through the clothing, for the purpose of arousing or
gratifying sexual desire of any person;
(4) "Sexual intercourse", any penetration, however slight, of the female sex organ by the male sex organ, whether or not an emission results.

Mistake as to incapacity or age–consent not a defense, when.
566.020. 1. Whenever in this chapter the criminality of conduct depends upon a victim’s being incapacitated, no crime is committed if the actor reasonably believed that the victim was not incapacitated and reasonably believed that the
victim consented to the act. The defendant shall have the burden of injecting the issue of belief as to capacity and consent.
2. Whenever in this chapter the criminality of conduct depends upon a child being thirteen years of age or younger, it is no defense that the defendant believed the child to be older.
3. Whenever in this chapter the criminality of conduct depends upon a child being under seventeen years of age, it is an affirmative defense that the defendant reasonably believed that the child was seventeen years of age or older.
4. Consent is not an affirmative defense to any offense under chapter 566 if the alleged victim is less than twelve years of age.
 


Marriage to victim, at time of offense, affirmative defense, for certain crimes.

566.023. It shall be an affirmative defense to prosecutions pursuant to sections 566.032, 566.034, 566.062, 566.064, 566.068, and 566.090 that the defendant was married to the victim at the time of the offense.

 Evidence that defendant has committed other charged and uncharged crimes of a sexual nature involving victims under fourteen admissible to prove propensity to commit crime, when.
566.025. In prosecutions pursuant to this chapter or chapter 568, RSMo, of a sexual nature involving a victim under fourteen years of age, whether or not age is an element of the crime for which the defendant is on trial, evidence that
the defendant has committed other charged or uncharged crimes of a sexual nature involving victims under fourteen years of age shall be admissible for the purpose of showing the propensity of the defendant to commit the crime or crimes
with which he or she is charged unless the trial court finds that the probative value of such evidence is outweighed by the prejudicial effect.

 Statutory rape and attempt to commit, first degree, penalties.
566.032. 1. A person commits the crime of statutory rape in the first degree if he has sexual intercourse with another person who is less than fourteen years old.
2. Statutory rape in the first degree or an attempt to commit statutory rape in the first degree is a felony for which the authorized term of imprisonment is life imprisonment or a term of years not less than five years, unless in the
course thereof the actor inflicts serious physical injury on any person, displays a deadly weapon or dangerous instrument in a threatening manner, subjects the victim to sexual intercourse or deviate sexual intercourse with more than one person, or the victim is less than twelve years of age in which case the authorized term of imprisonment is life imprisonment or a term of years not less than ten years.


Statutory rape, second degree, penalty.

566.034. 1. A person commits the crime of statutory rape in the second degree if being twenty-one years of age or older, he has sexual intercourse with another person who is less than seventeen years of age.

2. Statutory rape in the second degree is a class C felony.

 Sexual assault, penalties.
566.040. 1. A person commits the crime of sexual assault if he has sexual intercourse with another person knowing that he does so without that person’s consent.
2. Sexual assault is a class C felony.

Statutory sodomy and attempt to commit, first degree, penalties.
566.062. 1. A person commits the crime of statutory sodomy in the first degree if he has deviate sexual intercourse with another person who is less than fourteen years old.
2. Statutory sodomy in the first degree or an attempt to commit statutory sodomy in the first degree is a felony for which the authorized term of imprisonment is life imprisonment or a term of years not less than five years, unless in the course thereof the actor inflicts serious physical injury on any person, displays a deadly weapon or dangerous instrument in a threatening manner, subjects the victim to sexual intercourse or deviate sexual intercourse with more than one person, or the victim is less than twelve years of age, in which case the authorized term of imprisonment is life imprisonment or a term of years not less than ten years.

 Statutory sodomy, second degree, penalty.
566.064. 1. A person commits the crime of statutory sodomy in the second degree if being twenty-one years of age or older, he has deviate sexual intercourse with another person who is less than seventeen years of age.
2. Statutory sodomy in the second degree is a class C felony.

Child molestation, first degree, penalties.
566.067. 1. A person commits the crime of child molestation in the first degree if he or she subjects another person who is less than fourteen years of age to sexual contact.

2. Child molestation in the first degree is a class B felony unless:

(1) The actor has previously been convicted of an offense under
this chapter or in the course thereof the actor inflicts serious physical
injury, displays a deadly weapon or deadly instrument in a threatening manner,
or the offense is committed as part of a ritual or ceremony, in which case the
crime is a class A felony; or

(2) The victim is a child less than twelve years of age and:

(a) The actor has previously been convicted of an offense under
this chapter; or

(b) In the course thereof the actor inflicts serious physical
injury, displays a deadly weapon or deadly instrument in a threatening manner,
or if the offense is committed as part of a ritual or ceremony, in which case,
the crime is a class A felony and such person shall serve his or her term of
imprisonment without eligibility for probation or parole.

Child molestation, second degree, penalties.
566.068. 1. A person commits the crime of child molestation in the second degree if he or she subjects another person who is less than seventeen years of age to sexual contact.
2. Child molestation in the second degree is a class A misdemeanor unless the actor has previously been convicted of an offense under this chapter or in the course thereof the actor inflicts serious physical injury on any person, displays a deadly weapon or dangerous instrument in a threatening manner, or the offense is committed as part of a ritual or ceremony, in which case the crime is a class D felony.
 Deviate sexual assault, penalty.
566.070. 1. A person commits the crime of deviate sexual assault if he has deviate sexual intercourse with another person knowing that he does so without that person’s consent.
2. Deviate sexual assault is a class C felony.

Sexual misconduct involving a child, penalty–applicability of section–affirmative defense not allowed, when.
566.083. 1. A person commits the crime of sexual misconduct involving a child if the person:
(1) Knowingly exposes his or her genitals to a child less than fourteen years of age under circumstances in which he or she knows that his or her conduct is likely to cause affront or alarm to the child;
(2) Knowingly exposes his or her genitals to a child less than fourteen years of age for the purpose of arousing or gratifying the sexual desire of any person, including the child; or
(3) Knowingly coerces or induces a child less than fourteen years of age to expose the child’s genitals for the purpose of arousing or gratifying the sexual desire of any person, including the child.
2. The provisions of this section shall apply regardless of whether the person violates the section in person or via the Internet or other electronic means.
3. It is not an affirmative defense to prosecution for a violation of this section that the other person was a peace officer masquerading as a minor.
4. Sexual misconduct involving a child is a class D felony unless the actor has previously pleaded guilty to or been found guilty of an offense pursuant to this chapter or the actor has previously pleaded guilty to or has been convicted
of an offense against the laws of another state or jurisdiction which would constitute an offense under this chapter, in which case it is a class C felony.

 
Sexual contact with a student while on public school property.
566.086. 1. A person commits the crime of sexual contact with a student while on public school property if he or she has sexual contact with a student of the public school while on any public school property and is:
(1) A teacher, as that term is defined in subdivisions (4), (5), and (7) of section 168.104, RSMo;
(2) A student teacher;
(3) An employee of the school;
(4) A volunteer of the school or of an organization working with the school on a project or program; or
(5) A person employed by an entity that contracts with the public school district to provide services.
2. For the purposes of this section, "public school property" shall mean property of any public school in this state serving kindergarten through grade twelve or any school bus used by the public school district.
3. Sexual contact with a student while on public school property is a class D felony.
 Sexual misconduct, first degree, penalties.

566.090. 1. A person commits the crime of sexual misconduct in the first degree if such person purposely subjects another person to sexual contact without that person’s consent.
2. Sexual misconduct in the first degree is a class A misdemeanor unless the actor has previously been convicted of an offense under this chapter or unless in the course thereof the actor displays a deadly weapon in a threatening manner
or the offense is committed as a part of a ritual or ceremony, in which case it is a class D felony.

Sexual misconduct, second degree, penalties.
566.093. 1. A person commits the crime of sexual misconduct in the second degree if such person:
(1) Exposes his or her genitals under circumstances in which he or she knows that his or her conduct is likely to cause affront or alarm;
(2) Has sexual contact in the presence of a third person or persons under circumstances in which he or she knows that such conduct is likely to cause affront or alarm; or
(3) Has sexual intercourse or deviate sexual intercourse in a public place in the presence of a third person.
2. Sexual misconduct in the second degree is a class B misdemeanor unless the actor has previously been convicted of an offense under this chapter, in which case it is a class A misdemeanor.

Sexual misconduct, third degree, penalty.
566.095. 1. A person commits the crime of sexual misconduct in the third degree if he solicits or requests another person to engage in sexual conduct under circumstances in which he knows that his requests or solicitation is likely to cause affront or alarm.
2. Sexual misconduct in the third degree is a class C misdemeanor.

Sexual abuse, penalties.
566.100. 1. A person commits the crime of sexual abuse if he subjects another person to sexual contact by the use of forcible compulsion.
2. Sexual abuse is a class C felony unless in the course thereof the actor inflicts serious physical injury or displays a deadly weapon or dangerous instrument in a threatening manner or subjects the victim to sexual contact with
more than one person or the victim is less than fourteen years of age, in which case the crime is a class B felony.

Enticement of a child, penalties.
566.151. 1. A person at least twenty-one years of age or older commits the crime of enticement of a child if that person persuades, solicits, coaxes, entices, or lures whether by words, actions or through communication via the Internet or any electronic communication, any person who is less than fifteen years of age for the purpose of engaging in sexual conduct.
2. It is not an affirmative defense to a prosecution for a violation of this section that the other person was a peace officer masquerading as a minor.
3. Enticement of a child or an attempt to commit enticement of a child is a felony for which the authorized term of imprisonment shall be not less than five years and not more than thirty years. No person convicted under this section
shall be eligible for parole, probation, conditional release, or suspended imposition or execution of sentence for a period of five calendar years.