IN 1965 MARSHALL R. URIST [1] FIRST demonstrated that osteoinductive substances led to the formation of bone at extraskeletal sites, by observing that a new ossicle had formed after the implantation of demineralized bone matrix in a muscle pouch of a rat. Less than two decades later, Sampath and Reddi [2] in an in vivo bioassay separated insoluble demineralized bone matrix from the soluble morphogenetic protein responsible for this effect, which was named bone morphogenetic protein. Seven years later, Wozney et al. [3] identified the genetic sequence of bone morphogenetic protein, leading to the discovery of its different isoforms and later, in 1990 osteogenetic protein (OP-1) was cloned by Ozkaynak et al. [4].