Children 2 years of age and older with severe osteogenesis imperfecta (types III and IV) may be eligible for this study. Those enrolled will be randomly assigned to groups according to age; children two to four years of age will be randomly assigned to receive pamidronate every 3 or every 6 months. Children four years of age and older may participate in the growth hormone treatment groups. These children will continue on growth hormone until they reach their adult height or fail to grow as much as would be expected for someone on growth hormone.