MODEL RELEASED. Preparing sperm for IVF. Scientist placing a semen sample in a centrifuge. The centrifuge machine spins at very high speeds, separating the sperm from proteins in the semen. The sperm will be used for in vitro fertilisation (IVF). It will be injected into ova (eggs) to fertilise them and the resultant zygotes will be grown in the lab until they reach an early stage of embryonic development. They will then be implanted into the patient's uterus. This can result in multiple births. IVF allows infertile couples to conceive a child.