  Strict gauge invariance requires that physical left-handed leptons are
actually bound states of the elementary left-handed lepton doublet and the
Higgs field within the standard model. That they nonetheless behave almost like
pure elementary particles is explained by the Fr\"ohlich-Morchio-Strocchi
mechanism. Using lattice gauge theory, we test and confirm this mechanism for
fermions. Though, due to the current inaccessibility of non-Abelian gauged Weyl
fermions on the lattice, a model which contains vectorial leptons but which
obeys all other relevant symmetries has been simulated.
