In oocytes and oocytes of many animals, in the vicinity of the posterior pole (or vegetative) is specific morphologically different cytoplasm, so-called. plasma gender. During embryonic development, this plasma undergoes separation into blastomeres and germline cells prapłciowych. Plasma sexual contains numerous mitochondria, cisterns rough endoplasmic reticulum, Golgi complexes and nieobłonione characteristic structure, so-called. Grain sex. The plasma gender, as well as sexual beans are collected several classes of RNA (eg mRNA localized) and protein. The paper discussed the role of the plasma constituents gender specification (determination) germline; presents a modern methods used in studies of plasma sexual function.