Light micrograph of a micro-needle (right) and pipette (left) that are being used to fertilise a human egg cell (oocyte) during the process of in vitro fertilisation (IVF). The micro-needle was used to inject a human sperm cell into the human egg cell. This IVF technique is known as intracytoplasmic sperm injection (ICSI). The injected sperm fertilises the egg and the resulting zygote is then grown in the laboratory until it reaches an early stage of embryonic development. It is then implanted in the patient's uterus, where it develops into a foetus. IVF allows infertile couples to conceive a child.