MicroSort® is a sperm separation method based on the difference in the amount of genetic material in sperm. Sperm carrying an X chromosome has approximately 2.8% more DNA material than sperm carrying a Y chromosome.
During the MicroSort® process, the sperm sample is washed to remove seminal liquid and nonmotile cells. After the washing, the sample is stained with a special fluorescent material that attaches to the DNA contained in the sperm.
The stained sperm cells are analyzed one by one by a flow cytometer, in which cells pass through a laser to make the stain attach to the DNA fluoresce. The sperm containing the X chromosome (which have more DNA and therefore more stain) will shine brighter than the sperm containing the Y chromosome.
The flow cytometer uses a special software to identify X and Y chromosome sperm based on their fluorescence signature. The sperm carrying the chromosome that will produce the desired gender are separated from the rest of the sample — resulting in an enriched sperm sample ready for use.
The sorting process of each semen sample takes between 6 and 7 hours. Many assisted reproductive techniques allow MicroSort® to cryopreserve the samples for future use or for shipment to any part of the world.