A child's height is largely dependent on how tall his parents are. If both you and your partner are short, it's unlikely your child will go on to play pro basketball. You'll have a rough idea of your child's ultimate adult height once he turns 2 and is measured on the big-kid growth charts. There's also a calculation that can be done using both parents' height to predict a child's height potential. If your child is following his growth curves for his height, no worries. If your child's height seems to be plateauing or falling off his curve, then your pediatrician will do tests to look for a medical cause.
Boys who have a predicted height of less than 5 feet and girls who have a predicted height of 4 feet 9 inches or less are now able to receive human growth hormone (HGH), should a parent wish to give that to their child. Until recently, HGH was only used for patients with a true growth hormone deficiency. However, your child would first go through extensive testing with an endocrinologist, a doctor who specializes in body hormones. And, using HGH is a decision you would discuss with the endocrinologist.