S emen is put in a centrifuge tube, along with a more dense solution. The solution helps to separate the semen as it is spun in the centrifuge. A fter being spun in the centrifuge, the specimen divides into three parts O nce they are separated, each of these parts are subjected to testing. There's more than one way for HIV positive couples to attempt a safe pregnancy. In practice, though, the undertaking raises complicated questions.
Sperm washing is actually a common technique.
It's been used for years by infertility clinics to boost the potency of a man's semen when trying to help his female partner conceive. It takes advantage of the fact that sperm are small and heavy, and can move like tadpoles. The semen is put in a test tube which is then spun in a centrifuge to separate the sperm from the other cells and fluids. If both parts are negative, the isolate sperm are covered with a new solution, which the healthiest cells will swim their way into. If no virus is found in a second test on the sperm, they can be used to fertilize the woman's egg cells.