We compare the parallaxes of stars from VLBI astrometry in the literature to those in the Gaia DR2 catalog .
Our full sample contains young stellar objects , evolved AGB stars , pulsars and other radio stars .
Excluding AGB stars , which show significant discrepancies between Gaia and VLBI parallaxes , and stars in binary systems , we obtain an average , systematic , parallax offset of -75 \pm 29 ~ { } \mu as for Gaia DR2 , consistent with their estimate of a parallax zero-point between -100 and 0 \mu as .