CHILD

A son or daughter of any age, including biological children, unborn children, adopted children, stepchildren, foster children and any children born outside of marriage.

Legally, a child is defined as any individual under an age specified by the laws of a particular state, usually 14 or 16.  In this sense, a child can then be distinguished from a minor, who, in most states, is an individual under the age of 18. 

An emancipated individual whom is below the specified legal age of majority is often considered an adult rather than a child.