Baby's first teeth usually start coming in around 6 months of age, beginning with the lower front teeth. The teething process may cause some irritability in babies but usually does not result in serious issues like fever, diarrhea or vomiting. While teething, parents should rub inflamed gums and provide teething toys to chew on. It's also important to introduce solid foods like apples and carrots before 6 months so babies learn to chew in preparation for more teeth. Close supervision is needed once teeth emerge to prevent choking on small pieces.