  Elastic lepton scattering off of a nucleon has proved to be an efficient tool
to study the structure of the hadron. Modern cross section and asymmetry
measurements at Jefferson Lab require effects beyond the leading order Born
approximation to be taken into account. Availability of unpolarized beams of
both electrons and positrons in respective experiments would enable to reduce
systematic uncertainties due to higher-order charge-odd contributions. In
addition, information on an unpolarized electron-to-positron cross section
ratio could serve as a test for theoretical models that provide predictions for
charge-dependent radiative corrections to elastic lepton-nucleon scattering.
Availability of polarized beams of leptons would allow for even more
comprehensive study of higher-order effects as some of them are dominant in
polarized lepton-nucleon scattering asymmetries. We present a brief overview of
effects due to the lepton's charge and target's polarization on elastic
lepton-nucleon scattering measurements.
