Thank you very much for letting us see the enclosed submission. Unfortunately it does not suit the needs of the magazine at this time.
Your submission has been read by an editor, but the press of time and manuscripts (approximately 850 per month) does not permit personal replies or criticism. For your general information, though, most stories are rejected because they lack a new idea of theme. A great many of the ideas that may seem innovative to an SF newcomer are in fact overfamiliar to readers more experienced in the field. The odds greatly favor this being the case of this rejection.
Another common cause (all too common, we're afraid) of rejection is the obvious lack of basic English compositional skills on the part of the author. By this we mean that the writer has misspelled or misused everyday words, and/or mispunctuated same. Stories are rejected on this basis because a writer must be familiar with the tools of his or her trade, just as an electrician or carpenter must.
Finally, your story may have been rejected, not because it lacked a new idea, or was misspelled or mispunctuated, or because the writing was not "professional" enough, but simply because it failed to rise far enough above the other 849 seen that month.