So we are not yet sure exactly what mechanism accounts for the neutrino masses. One possible mechanism is the seesaw mechanism. Am I correct in thinking: Majorana mass terms are born from couplings between particles and antiparticles. This violates lepton number conservation and charge conservation. Therefore only neutral particles can have Majorana mass terms, i.e neutrinos. However that still does not account for lepton number. Is it therefore a requirement that neutrinos be there own antiparticle (i.e Majorana particles) for Majorana terms to exist so as to conserve lepton number?