  We shortly summarize the two-families scenario in which both hadronic stars
and strange quark stars can exist and we describe the main predictions one can
obtain from it. We then concentrate on the observables that most likely will be
measured in the near future, i.e. masses, radii, tidal deformabilities and
moments of inertia and we present a list of objects that are candidate strange
quark stars in this scheme. We show that the estimates of the radii derived up
to now from observations are all compatible with the two-families scenario and
in particular all the objects having large radii can easily be interpreted as
strange quark stars.
