Homo duplex -- a divided human; the belief that a human being is comprized of an antagonism between (1) the instinctual desires of the human animal (think of the four "Fs") and (2) the desire to follow and obey societal pressures (rules, morals, & ethics) to maintain self-control (see E. Durkheim).
In genetics its product of hybridization of two homologous lengths of DNA, in contrast to a hetroduplex which is the opposite.