D.C. Code § 46-404

A proceeding to declare the nullity of a marriage may be instituted in the case of an infant under the age of consent by such infant, through a next friend, or by the parent or guardian of such infant; and in the case of a person with mental illness, by next friend. But no such proceedings shall be allowed to be instituted by any person who, being fully capable of contracting a marriage, has knowingly and wilfully contracted any marriage declared illegal by the foregoing sections.