The vast majority of babies sprout their first teeth when they're between 4 and 7 months of age. An early developer may get his first white cap as early as 3 months, while a late bloomer may have to wait until he's a year old or more. (In rare cases, a baby's first tooth is already visible at birth.) Whenever the first tooth makes its appearance, celebrate the milestone by taking pictures and noting the date in your child's baby book.
Teeth actually start developing while your baby's in the womb, when tooth buds form in the gums. Teeth break through one at a time over a period of months, and often — but not always — in this order: First the bottom two middle teeth, then the top two middle ones, then the ones along the sides and back. They may not all come in straight, but don't worry — they usually straighten out over time.