Abstract: Male infertility significantly impacts approximately half of all couples struggling with infertility. A notable proportion of male infertility cases are classified as idiopathic, where the cause remains unidentified. Traditionally, sperm DNA has been the primary focus in understanding the males contribution to fertilization. However, recent studies emphasize the critical roles of various sperm transcripts and proteins in processes like the acrosome reaction, sperm-oocyte fusion, and subsequent embryo development. This review offers a thorough and current examination of the molecular biology underlying spermatogenesis. It highlights the evidence for spermatogenetic failure, with a particular focus on the molecular factors carried by sperm that are vital for oocyte fertilization and embryonic growth. This information serves as a foundational step toward discovering new diagnostic markers and potential therapeutic targets for what is currently classified as idiopathic male infertility.