How can marriage to a woman of unknown lineage be permissible when her parents are not known, and what would be the response if she were among the the suitor's mahārim (unmarriageable kin)?

It is recommended to marry a woman of known lineage and disliked to marry one of unknown lineage, such as a foundling, even though marriage to her is permissible. The general principle is that women are permissible except for what has been explicitly forbidden in Islamic law due to lineage, affinity, or suckling, as Allah Almighty says after mentioning the forbidden women: "And lawful for you are [all others] besides those." Therefore, marriage to a woman of unknown lineage is permissible.