It sounds like you are angry with your son and disappointed in him because he isn't drawn to sports as you were. You need to ask yourself why this bothers you so much. Do you think all boys should play sports in order to be masculine, to grow up right? Are you afraid that you are raising a sissy as well as a geek? Who put those fears in your mind? Unless and until you get help in finding out why this issue troubles you so much, you will continue to send your son the message that he is not what you want in a son. Hearing that repeated message, both directly and indirectly, will harm him immeasurably.
If you can look back into your own childhood, be honest about what you wanted but didn't get, and consider how that has affected you as an adult, you may begin to understand why you feel this way about your son. Giving the Love That Heals, by Hendrix and Hunt, can help you with that examination. I know that to some degree you feel guilty and disappointed for feeling this way about a perfectly wonderful son. A few counseling sessions might be extraordinarily helpful in discovering why you are hurting so much.
Your son deserves a mother who will love him and appreciate him for who he is. You deserve a chance to be that mother. Please get the help that will allow both of you to be who you were meant to be as mother and son. Thanks for having the courage to write.