: : : If she doesn't have any then I must venture to ask this: I don't really know too much about Roman Catholic values but is it possible that Tolkien made her childless to keep her "pure", so to speak, in a sense, if you know what I mean???

: : she did. at least one, possibly more. the certain one, according to the geneologies, is celebrian (who later married elrond, i believe). also a possibility, according to one story (given in unfinished tales), is that amroth was also born of galadriel and celeborn, but since other versions contradict this, it's not stated as a fact.
: Does anybody have any idea, why, despite the very long lives of the Elves, they did not have numerous children. Could it be that there is a connection to the reincarnation principle, wherby Elves could be born again, and maybe, if there weren't any souls around wiating to be reincarnated, there simply weren't any births?

There is evidence to suggest that a certain amount of the parents' "spirit" (or "essence") is transfered into the child at birth. This is why Miriel died after giving birth to a son with such a fiery spirit (and this also explains why Feanor was able to sire so many children). This is one reason why the Elves slowly decay: the child is never as powerful as the parents. And the more children an Elf has, the less power each child will have.