We present results of random simulations for the expected isotropic distrib
utions of the polar and azimuthal angles of galaxy rotation axes. It is fou
nd that selection effects concerning position and inclination of galaxies c
an remarkably change the shape of these distributions. Selection effects of
this kind may play an important role when galaxies are taken from an incom
plete dataset (e.g. from a limited region of the sky). These effects can le
ad to artificial structures (and hence to misinterpretations, as it already
happened in the literature) and should be taken into account when deciding
upon isotropy or anisotropy in the spatial distribution of spin vectors of
galaxies. In this paper we discuss the various effects of selection.