Many new parents want to know exactly when to expect that next milestone. What I tell them is this: Infant growth can be viewed as a developmental elevator. Your baby rides up from floor to floor, stopping at each level to learn a new skill. With nurturing and care, she graduates to the next stage at a pace determined in part by her genes and her temperament. Babies also build skills based on the environment they find on each floor. If the interaction with her caregivers is responsive and enriching, she is more likely to get back on the elevator with more skills, making the ride up to the next stage smoother.
That said, there's a wide range of what's considered "normal" infant development. Babies spend different amounts of time at each stage before moving on to the next one. Some make a brief stop at one level and quickly progress to the next; others seem to skip a stage entirely. Knowing this may help you avoid the neighborhood race to see whose baby sits or crawls or walks first. Here, a guide to the milestones that your child is reaching during this action-packed time.
Contributing editor William Sears, M.D., is the author, with his wife, Martha Sears, R.N., of The Baby Book.