Newborn babies will not have teeth yet, on average by the 6th month, the baby will start to have the first tooth, by 12 months there will be about 6 teeth and by 24 months there will be a full set of 20 baby teeth, 10 in the upper jaw and 10 in the lower jaw. The baby teething schedule will be different for each child but the difference in time is usually less than a year.