  We calculate electromagnetic neutral pion production off three-nucleon bound
states (3H, 3He) at threshold to leading one-loop order in the framework of
chiral nuclear effective field theory. In addition, we analyze the dependence
of the nuclear S-wave amplitude E_{0+} on the elementary neutron amplitude
E_{0+}^{pi0 n} which in the case of 3He provides a stringent test of the
prediction based on chiral perturbation theory. Uncertainties from higher order
corrections are estimated.
