The age-related decline in female fertility has been attributed to a variety of causes including progressive oocyte depletion, meiotic irregularities and mitochondrial dysfunction. However, additional factors could potentially be involved. To explore this possibility, comprehensive analysis of gene expression in human oocytes, discarded following IVF procedures and segregated by age, was undertaken using microarray methods. These findings indicate that the expression of oocyte genes, in a variety of major functional categories including cell cycle regulation, cytoskeletal structure, energy pathways, transcription control, and stress responses, are influenced by maternal age. These results are corroborated by a complementary extensive study using mouse oocytes.