My son is 7 and on his well visit blood test showed that he produces enough blood cells but the cells are small? what does that mean and effects?

Mine are too: No danger. Mine run at the bottom of the reference range; since i'm of mixed racial heritage it may be a mild Alpha thal, or just because i've been a frequent blood donor. Some physicians would run a serum iron check to screen for iron deficiency that hasn't led to anemia yet. If below 70 fl, perhaps this is thal minor -- do you or dad have this? If dr is not concerned, i would not be either.

Evaluation of : Hemoglobin. What you described suggests that your son carries a thalassemia gene. If a person with beta thalassemia trait, hemoglobin may be slightly low and red cells are small. If your son does not have iron deficiency, it may be prudent to get hemoglobin evaluation done.