“…Direct comparisons in pregnancy rates achieved between simple centrifugation and sperm separation procedures, combined with low-dose insemination, will be necessary to determine if the extra time and expense required for improving the quality of the inseminate is justified. It may also be possible that the preferential selection of sperm entering the oviducts [39][40][41] is as efficient in selecting normal sperm as processing the ejaculate before insemination.…”