The concept was initially developed in the 1970s, gaining popular interest with the publication of a series of books in the late 1990s and the release of several films in the following decade. A variety of [[books]], conferences and related materials have been created surrounding the idea of indigo children, which have been criticized for a means of making money from credulous parents. | The concept was initially developed in the 1970s, gaining popular interest with the publication of a series of books in the late 1990s and the release of several films in the following decade. A variety of [[books]], conferences and related materials have been created surrounding the idea of indigo children, which have been criticized for a means of making money from credulous parents. |