In vitro fertilisation. Conceptual computer artwork of two sperm cells (spermatozoa, the male sex cell) and an egg (ovum, the female sex cell) in a conical flask. This image represents in vitro fertilisation (IVF), where an egg is fertilised by sperm in a laboratory. The resulting zygote is grown in the lab until it reaches an early stage of embryonic development. It is then implanted in the uterus (womb). IVF allows infertile couples to conceive a child.