21.   But a niece decided to help them by having a child by carrying their fertilized egg.

22.   But according to one team, they include many embryos in various stages of development, and possibly even the fertilized egg of a microscopic organism.

23.   Clear Springs has its own brood stock, the fish that produce fertilized eggs.

24.   Conjoined twins occur when a single fertilized egg fails to divide completely to form identical twins.

25.   Conjoined twins are always identical, because they always come from a single fertilized egg, and so are always the same sex.

26.   Currently, researchers can cull stem cells from unwanted fertilized eggs at fertility clinics.

27.   Doctors then implanted four fertilized eggs, with two surviving the process.

28.   Donating fertilized eggs to infertile couples means that a couple might have a genetically related child raised by someone else.

29.   Each of the three choices regarding unused fertilized eggs has drawbacks.

30.   Early on in human development, the multiplying cells of the fertilized egg give rise to an outer layer of tissue called the ectoderm.