The inventive technology relates to methods and apparatus for reducing proteincontent in sperm cell extenders and may include one or more of the followingfeatures: techniques for reducing protein content in a sperm cell extender；techniques for reducing protein content in a cryoprotectant-containing Bfraction of a sperm cell extender； techniques for preparing sperm cellextenders that do not require clarification； techniques for preparing lowdensity gradient sperm cell extenders suitable for centrifugation； techniquesfor reducing protein content between individual steps in preparing a spermcell extender, and techniques for establishing novel values of reduced proteincontent in sperm cell extenders.
