SDCL § 25-6-1: Child born to unmarried mother--Acknowledgment by father--Effect.

If the biological mother of a child is not married to the father of the child at the time of the conception or birth of the child, or at any time between conception and birth of the child, the father becomes an acknowledged father of the child and adopts the child only by:

(1) Openly holding out the child as the father's own by receiving the child into the father's household;

(2) Voluntarily contributing to the financial support of the child; or

(3) Voluntarily contributing to the daily supervision, protection, education, and care of the child.

Following a father's adoption of a child pursuant to this section, the child is deemed for all purposes to be the child of the father from the time of the child's birth. No other provision of law relating to adoption shall apply.