The spectral functions and light-cone momentum distributions of protons and
neutrons in He-3 and H-3 are given in terms of the three-nucleon wave func
tion for realistic nucleon-nucleon interactions. To reduce computational co
mplexity, separable expansions are employed for the nucleon-nucleon potenti
als. The results for the light-cone momentum distributions suggest that the
y are not very sensitive to the details of the two-body interaction. as lon
g as it has reasonable short-range repulsion. The unpolarized and polarized
structure functions are examined for both He-3 and H-3 in order to test th
e usefulness of He-3 as a neutron target. It is found that the measurement
of the spin structure function of polarized H-3 would provide a very clear
test of the predicted change in the polarized parton distributions of a bou
nd proton.