The inventive technology relates to methods and apparatus for reducing protein content in sperm cell extenders and may include one or more of the following features: techniques for reducing protein content in a sperm cell extender； techniques for reducing protein content in a cryoprotectant-containing B fraction of a sperm cell extender； techniques for preparing sperm cell extenders that do not require clarification； techniques for preparing low density gradient sperm cell extenders suitable for centrifugation； techniques for reducing protein content between individual steps in preparing a sperm cell extender, and techniques for establishing novel values of reduced protein content in sperm cell extenders.
