Mo. Rev. Stat. § 451.160: Names of children born before marriage shall be recorded.

The reputed father and mother of children who were born before the ceremony of marriage is performed, as provided by this chapter, may, at the time of solemnization of said marriage, give to the officer the names of their children then living, or the descendants of such as may be dead; and it shall be the duty of such officer to record such names with his certificate of marriage.