210.819.  Parent and child relationship, how established. — The parent and child relationship between child and:

 (1)  The natural mother may be established by proof of her having given birth to the child, or under the provisions of sections 210.817 to 210.852;

 (2)  The natural father may be established under the provisions of sections 210.817 to 210.852;

 (3)  An adoptive parent may be established by proof of adoption.