No one knows where it originated. If you're going to use classical sources, you have to know what they said and use expert secondary sources. For example, we only know of Agatharchides through other writers, and what they said about FGM remains unclear. You seem to be trying to push a personal view and looking for sources that support it, rather than using the most appropriate sources (e.g. ancient historians for ancient history), and sticking closely to what they say.  (talk)