Mo. Rev. Stat. § 376.580: Misrepresentation.

No misrepresentation made in obtaining or securing a policy of insurance on the life or lives of any person or persons, citizens of this state, shall be deemed material, or render the policy void, unless the matter misrepresented shall have actually contributed to the contingency or event on which the policy is to become due and payable, and whether it so contributed in any case shall be a question for the jury.