In the Iranian legal system, according to the fatwa of some Islamic jurists, marriage of a virgin daughter is subject to the permission of her father or paternal grandfather (Article 1043 of the Civil Code). However, considering a case where girl's lack of virginity is due to sexual intercourse, and she is to marry under these circumstances, some courts have issued conflicting judgments regarding whether guardianship still remains or is extinguished. For this reason, the General Board of the Supreme Court issued binding precedent No. 1, dated February 18, 1985. Relying upon criteria extrapolated from the first part of the above-mentioned article and the fatwa of some Islamic jurists, the Supreme Court has evaluated sexual intercourse, be it legitimate or illegitimate, to cause extinguishment of guardianship, and on this basis, has judged such a marriage to be valid. In this research, the abovementioned binding precedent, which has not been comprehensively reviewed in Iranian legal literature, is examined with a descriptive and analytical method. And it was concluded that the influence of some jurists' fatwas, contrario argument 'argument from the contrary', derived from Article 1043 of the Civil Code of the type that provides an explanation about the subject, i.e. "the marriage of a non-virgin girl is not subject to the permission of her father or her paternal grandfather", fairness, the need to exercise precaution issues related to family affairs and the desirability of removing an element that provides a fertile ground for sin, to be satisfied with what is certain, the need to return to the principles of lack of guardianship and that all things are presumed to be lawfully done, can be mentioned as justification for this decision. However, this decision may be open to criticism for opening the way to fraus legis (fraud upon law) and not being bound by loss of virginity due to sexual intercourse and lack of guardianship due to other reasons, such as the girl being a minor or insane.