Sweet gum trees are popular and beautiful.  The are monoecious which means that they have both male and female reproductive organs.  They produce a "gum ball," or a small fruit that is hard and spiny.  Although some people really enjoy these trees, some people are turned off by the fruit that is produced.  

We are often asked about how to stop the sweet gum from fruiting.  Unfortunately, this is going to be a short post.  There is no way to prevent the "gum balls" that are produced, at least that we are aware of.  I guess I should rephrase that.  We have never run across a way to not damage the tree and prevent the fruit from being produced.  You could always remove the tree if worst came to worse.  If you don't like trees that drop items in your yard, you may want to think about planting something else.