  We propose that some of the high-latitude unidentified EGRET gamma-ray
sources could be the result of gravitational lensing amplification of the
innermost regions of distant, faint, active galactic nuclei. These objects have
gamma-ray emitting regions small enough as to be affected by microlensing of
stars in interposed galaxies. We compute the gravitational amplification taking
into account effects of the host galaxy of the lens and prove that, whereas the
innermost gamma-ray regions can be magnified up to thousand times, there is no
amplification at radio frequencies, leading to the observed absence of strong
counterparts. Some new effects in the spectral evolution of a gravitational
microlensed gamma-ray AGN are predicted. Within a reasonable range of lensing
parameters, and/or types of sources, both variable and non-variable EGRET
detections at high latitudes can be explained by microlensing. The same
phenomenon could also have an important incidence among the future GLAST
detections at high-latitudes.
