The technique involves a series of precise maneuvers performed under microscopic magnification to pick up a single live sperm and inject it directly into the interior of a human egg. The procedure requires that the female partner undergo ovarian stimulation with fertility medications so that several mature eggs develop. These eggs are then aspirated through the vagina, guided by vaginal ultrasound. After the eggs are harvested, each egg must be treated with a solution containing hyaluronidase, an enzyme which loosens and removes most of the cumulus cell surrounding the egg. This is followed by mechanically stripping the remaining cumulus cells off each egg. Stripping has to be done quickly yet gently so the egg is not harmed. Once stripped, the eggs are examined to see if they are mature. Only mature eggs will be injected with a sperm. The semen sample is prepared as described in intrauterine insemination section. The sperm preparation process separates live sperm from debris and most of the dead sperm. The embryologist searches under the microscope at 200 to 400 x magnification for a single normal or near normal appearing live sperm, immobilizes the sperm, picks it up in an extremely thin glass needle, and gently injects it directly into the egg.