  Giant molecular clouds (GMCs) are the major reservoirs of molecular gas in
galaxies, and the starting point for star formation. As such, their properties
play a key role in setting the initial conditions for the formation of stars.
We present a comprehensive combined inteferometric/single-dish study of the
resolved GMC properties in a number of extragalactic systems, including both
normal and dwarf galaxies. We find that the extragalactic GMC properties
measured across a wide range of environments, characterized by the Larson
relations, are to first order remarkably compatible with those in the Milky
Way. Using these data to investigate trends due to galaxy metallicity, we find
that: 1) these measurements do not accord with simple expectations from
photoionization-regulated star formation theory, 2) there is no trend in the
virial CO-to-H2 conversion factor on the spatial scales studied, and 3) there
are measurable departures from the Galactic Larson relations in the Small
Magellanic Cloud -- the object with the lowest metallicity in the sample --
where GMCs have velocity dispersions that are too small for their sizes. I will
discuss the stability of these clouds in the light of our recent far-infrared
analysis of this galaxy, and I will contrast the results of the virial and
far-infrared studies on the issue of the CO-to-H2 conversion factor and what
they tell us about the structure of molecular clouds in primitive galaxies.
