S.D. Codified Laws § 25-8-57
Any child born in wedlock, or born within ten months after dissolution of the marriage, is presumed legitimate to that marriage even if the marriage is subsequently declared to be null and void, or subsequently dissolved by divorce. This rebuttable presumption of legitimacy can only be disputed by the husband or wife, or a descendant of one or both of them, or a potential biological father of the child. The potential biological father has standing to file an action to rebut this presumption prior to obtaining genetic test results. The potential biological father may not rebut the presumption without genetic test results meeting the requirements of § 25-8-58 establishing that he is the biological father of the child.
This presumption may be specifically rebutted pursuant to § 25-8-64.
SDCL 25-8-57