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.

In business, this is a product, remote office, employee, etc., who doesn't get respect. The moniker stems from the popular slang phrase "beat you like a red-headed stepchild." Often times, the disrespect is undeserved.

If a product is an embarrassment to a company, it is the company's red-headed stepchild.

A term that originated out of the common mistreatment and social ostracism of redheaded individuals (gingers). A redheaded individual born into(legitamately or not), or adopted into a family of non-redheads was typically subject to physical and emotional abuse, and usually short handed when it came to financial matters in the family, such as the estate or any savings the family had acquired. Today, the term can be applied to an individual or group of individuals who are outcasts, or are typically dealt the worst hand in society.

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.

Term from rural America describing person who is socially outcast and easily picked on. Usually meeting the business end of a fist, boot, broomstick, bat, broken bottle, and/or foreign objects of injurious force. Often at the end of the tag line, "I'll beat you like a..."

Noun/Adjective: When someone is extremely undesirable and irrelevant in a group. In some instances you can refer to objects as such.

One who is beaten often.