Teething can cause some babies to be fussy, overly tired or a little feverish, but a baby with the above symptoms is most likely sick. It's a biological coincidence that teeth begin coming in at about 6 months -- the same time the immunity a baby receives from his mother starts to wear off and he must defend himself against the bugs that cause minor illnesses. If your baby seems sick (he may also be fussier, eat less, or be more lethargic than usual), he probably is. For instance, if your teething baby is tugging her ears, your first concern should be an ear infection. But let your doctor make the call -- and never attribute any symptom to teething without first having your pediatrician rule out other causes. --Janine Musick
Originally published in the September 2000 issue of Parents magazine. Updated 2009.