Totipotency is the ability of a cell to develop into a complete organism, provided the relevant external conditions are fulfilled. Cf. § 8 of the German Embryo Protection Act (ESchG) which specifies that

"(1) For the purpose of this Act, an embryo already means the human egg cell, fertilised and capable of developing, from the time of fusion of the nuclei, and further, each totipotent cell removed from an embryo that is assumed to be able to divide and to develop into an individual under the appropriate conditions for that.

(2) In the first twenty-four hours after nuclear fusion, the fertilised human egg cell is held to capable of development except when it is established before expiry of this time period that it will not develop beyond the one-cell stage.

(3) Germ line cells, for the purpose of this Act, are all cells that lead of the egg and sperm cells to the resultant human being and, further, the egg cell from capture or penetration of the sperm cell until the ending of fertilisation by fusion of the nuclei."

An overview of early embryonic development with particular regard to the ethically and legally relevant phenomena of totipotency and pluripotency can be found in: