During the heyday of the touring stock company, when whole families traveled and performed together, children grew up filling out crowd scenes. At mid-century there was a fad for putting talented children into adult roles and presenting them as novelties; the little Bateman sisters as Richard III and Richmond best exemplify the practice. On the modernist stage, however, it was more usual to put child performers into plays with strong roles for children like Little Eva in Uncle Tom's Cabin and the title character in Little Lord Fauntleroy. Plays written for children were part of the American theatre from its beginnings, and World War I children's theatre* emerged as a potent subgenre.
The Historical Dictionary of the American Theater. James Fisher.