In the early 1980s, by the determination of the Boorola gene (FecB) in Booroola sheep with high ovulation rate, there has been a great interest for identification of genes that are responsible for prolificacy and their use in breeding programs.The mutation occurred in Bone morphogenetic protein 15 (BMP15), Bone morphogenetic protein-1B (BMPR-1B) and Growth differentiation factor 9 (GDF9) genes have been found to increase the ovulation rate. Additionally some others gene are known to exist based on expressed inheritance patterns although the location of mutations has yet to be found. In the BMP15 gene, with almost the same phenotypic expression eight distinct mutations have been recognized, among themHanna (FecXH) andInverdale (FecXI) were identified first in Romney sheep in New Zealand. X-linked dominant genes with sterility in homozygous females are the modes of inheritance of the BMP15 gene. A total of 88 prolific Awassi sheep were screened for the presence of the FecXI mutation in the BMP15 gene and FecXI mutation was not found in any of the sheep tested.