  We compare radio profile widths of young, energetic gamma-ray-detected and
non-gamma-ray-detected pulsars. We find that the latter typically have wider
radio profiles, with the boundary between the two samples exhibiting a
dependence on the rate of rotational energy loss. We also find that within the
sample of gamma-ray-detected pulsars, radio profile width is correlated with
both the separation of the main gamma-ray peaks and the presence of narrow
gamma-ray components. These findings lead us to propose that these pulsars form
a single population where the main factors determining gamma ray detectability
are the rate of rotational energy loss and the proximity of the line of sight
to the rotation axis. The expected magnetic inclination angle distribution will
be different for radio pulsars with and without detectable gamma rays,
naturally leading to the observed differences. Our results also suggest that
the geometry of existing radio and outer-magnetosphere gamma-ray emission
models are at least qualitatively realistic, implying that information about
the viewing geometry can be extracted from profile properties of pulsars.
