in the default Gdm and fedora -- no
the version of GDM that fedora uses is a hacked "just working-very bacic" version of the not done alpha svn version. gdm is NOT completely wrote nor done . It is a UNDER COOKED cookie .
for auto login use KDE's KDM to boot
KDM can log into Gnome
search the "fedoraforum" for it . There are many posts on that.