The term 'virgin birth' is a reference to the phenomenon of parthenogenesis, which is a form of asexual reproduction in which an embryo develops from an unfertilized egg. This process can occur naturally in some species of animals, such as certain lizards and fish, and has been artificially induced in other species, such as chickens and turkeys. In humans, parthenogenesis is not possible, but the term 'virgin birth' is often used to refer to the miraculous conception of Jesus Christ in Christianity.