'autogenous' originates from Greek, specifically the word 'autogenēs', where 'auto-' meant 'self' and 'genēs' (from 'genos') meant 'born' or 'kind'.

'autogenēs' passed into scientific/late Latin/modern formation as 'autogenēs'/'autogenes' and then into English as 'autogenous', with the adverbial suffix -ly producing 'autogenously'.

Initially it meant 'self-born' or 'self-produced'; over time it came to be used broadly in scientific and general contexts to mean 'produced from within' or 'spontaneously', a meaning that has largely been retained.