Illinois Statutes Chapter 750. Families § 5/212. Prohibited Marriages

(1) a marriage entered into prior to the dissolution of an earlier marriage, civil union, or substantially similar legal relationship of one of the parties, unless the parties to the marriage are the same as the parties to a civil union and are seeking to convert their civil union to a marriage pursuant to Section 65 of the Illinois Religious Freedom Protection and Civil Union Act;

(2) a marriage between an ancestor and a descendant or between siblings, whether the relationship is by the half or the whole blood or by adoption;

(3) a marriage between an uncle and a niece, between an uncle and a nephew, between an aunt and a nephew, or between an aunt and a niece, whether the relationship is by the half or the whole blood;

(4) a marriage between cousins of the first degree; however, a marriage between first cousins is not prohibited if:

(5) (blank).