Abstract: A system for purifying sperm for use in an assisted reproductive technique procedure is provided. The system includes a sperm filter through which a chemoattractant and a sperm specimen are pumped. When the chemoattractant is pumped into the filter a gradient is formed of chemoattractants having varying concentrations. Sperm that is desirable will swim toward the higher concentrated chemoattractant and are collected by a sperm collection outlet, while sperm that are immotile and unpreferred are unable to swim across the gradient are collected by a waste collection outlet.