Sperm taken from a male goat is combined with a female's egg in a petri dish. The resulting embryo is implanted into the female's uterus to develop

A sheep embryo, comprised of 16 cells, is removed from the mother's uterus and separated into individual cells. Each cell multiplies creating 16 separate embryos, which are implanted into 16 different sheep to mature.

Three eggs are removed from a female mouse, and their nuclei removed and discarded. Nuclei taken from the cells of the second female mouse are inserted into the eggs. The resulting eggs are allowed to multiply into embryos, then implanted into surrogate mothers.

A cow with many desirable traits is stimulated to produce many egg cells. Each of these egg cells (not identical) are fertilised and implanted into a surrogate mother.

Sperm from a prize bull is used to impregnate cows in different parts of the world

Researchers want to bring back the wolly mammoth! They collect a tissue sample from a wolly mammoth that has been frozen in a block of ice for thousands of years. From cells in this sample, they collect several nuclei, which they insert into egg cells from another species.

The resulting embryos are implanted into a surrogate mother and carried to term