2,233. Why Only Men Must Investigate

Hilchos Issurei Biah 19:21

The reason that a man must investigate the lineage of a woman he wants to marry from a family whose pedigree has been called into question but a woman need not do so regarding a man is because women of halachically valid lineage were not enjoined against marrying men of impaired pedigree.

Hilchos Issurei Biah 19:22

If a person is called a mamzer, a Gibeonite, a chalal or a servant and he says nothing, his lineage and that of his family is called into question. One may not marry women from this family until the previously-described investigation has been made.