The Sons of Earth was an organisation of humans during Earth's Imperial period.
They were opposed to the colonisation of other worlds, the exploitation of their resources, the disruption of native peoples and the destruction of native ecosystems.
Rohm-Dutt pretended to be working for them, supplying guns to the Swampies, when he was in fact an employee of the refinery on Delta III. The owners of the refinery hoped that the Swampies would attack the refinery, justifying their extermination.
Rohm described the Sons of Earth as a "crank" organisation that wanted all humans to return to Earth and starve. (DW: The Power of Kroll)