red headed stepchild

A child who is obviously not your own, a child who is treated worse than other children in the family

With red hair being rare, a child born to non red headed parents was often assumed to be the child of an affair. Thus was treated badly, usually in the form of beatings.

A person or group treated without the favor of birthright.

Possible source: the story of King David's lineage. According to midrash (exegetical works on the Bible), his father Jesse separated from his mother due to concern about his own Jewish lineage with the intent not to procreate with her any longer. He planned to have more children with a non-Jewish maidservant who instead conspired with his wife to allow her to be with him one more time. She conceived and when it became apparent that she was pregnant the family wanted to ostracize her for her suspected infidelity. Her youngest son David (who is described in the Bible as being of ruddy complexion and having red hair) was shunned by the rest of Jesse's children - they wouldn't allow him to eat at the family table, and purposely assigned him to the role of shepherd in the hopes that he'd be devoured by wild animals. It wasn't until the prophet Samuel anointed him as the successor to Saul as King of Israel that doubts of his lineage were laid to rest.

Stepchild can be seen as a euphemism for bastard.

One who is beaten often.

According to popular belief red headed stepchildren are prone to severe discipline problems, rebelliousness and promiscuity.

Usually the most loved child in a familial unit. (Step)Parents pride this child for their distinct good looks and amazing personality. Women LOVE a redhead. That's a fact.