This article is from the Recreational Figure Skating FAQ, by Karen Bryden with numerous contributions by others.
Most people have a more or less strong innate preference for rotating
counterclockwise. This is because a counterclockwise rotation tends to
be controlled predominantly by the right shoulder, which is the
dominant one for a majority of people (although it is not true that
all right handed people prefer to turn counterclockwise!). In
addition, most rinks impose a counterclockwise direction of travel in
public sessions, which may reverse an initial predilection for turning
in the other direction.
Some beginner skaters seem not to have a strong natural direction
preference and are able to master some of the basic jumps in both
directions, but their instructors push them to settle on one side or
the other before moving on to more advanced skills. Part of the reason
for this is that spins are used as stepping stones to jumps. The back
spin in particular is used as a preliminary to the loop, which is in
turn used as a preliminary to the Axel. Ultimately, rotation for all
jumps is the same and it all comes from the backspin.
Although there is no reason why most skaters should not be able to
learn spins and jumps in both directions, in the practice you don't
get sufficient credit from the judges to make it worth the trouble of
learning to do them in the weaker direction. The only skating program
where reverse jumps are eventually required is ISI.