  Given two points of a Generalized Robertson-Walker spacetime, the existence,
multiplicity and causal character of geodesic connecting them is characterized.
Conjugate points of such geodesics are related to conjugate points of geodesics
on the fiber, and Morse-type relations are obtained. Applications to
bidimensional spacetimes and to GRW spacetimes satisfying the timelike
convergence condition are also found.
