The Genuine Carnegie Stages

Dianne N. Irving
Copyright September 8, 2013
Reproduced with Permission

For a while now I have noticed websites that claim to be presenting the Carnegie Stages of Early Human Embryonic Development, but do not. They use the name, but not the same accurate empirical facts documented by the genuine Carnegie Stages, and updated continuously since 1942 by the international nomenclature committee on human embryology (FICAT): This is even true for some Swiss websites.

Needless to say, the Stage most falsified is Stage 1 -- which consists of three phases (a, b, and c) that take place throughout the process of sexual reproduction, i.e., fertilization. The new single-cell human embryo/human being begins to exist at the beginning of that process -- at Stage 1a (the "primitive" embryo). That embryo is an embryo -- not just a "cell". The embryo then develops further to Stage 1b (the "ootid"), and then to Stage 1c (the "zygote"). Note that the zygote is not when the new human embryo begins to exist. (It also has no nucleus.)

The purpose of such falsification is to try to claim that the earliest human embryo is not an embryo yet (what I call a "pre-embryo" substitute!). Rather, they state or imply, it is just a "cell" -- not an already existing human being/organism. Therefore they can justify the use of these earliest human embryos in destructive experimental research. People need to realize how many living human embryos are being destroyed in all the new cloning, genetic engineering, synthetic biology and nanotechnology research -- all ethically "justified" by citing false Carnegie Stages websites. The bits and pieces of these embryos can also thus be mined for use in stem cell research (using the embryo's genes or organelles), production/marketing of culture media, feeder cells, assays, "controls", etc.

The genuine Carnegie Stages also document human asexual reproduction in Stages 2 - 5 in explaining naturally occurring human identical "twinning" (monozygotic twinning, or MZ).

FYI, here are the URLs for the accurate genuine Carnegie Stages:


National Museum of Health and Medicine
Developmental Anatomy Center

** URLs for all 23 Stages:

** Stage 1 (a, b, c,):

** URLs for asexual reproduction in Stages 2 - 5:


Originally developed as collaboration between embryologist Dr. Raymond Gasser at Louisiana State University Health Science Center (LSUHSC) and the Human Developmental Anatomy Center (HDAC) in Washington D.C.

** Stage 1 (a, b, c):

-- DVD: The Biology of Prenatal Development

Endowment for Human Development

-- iPhone ap: Embryo

National Library of Medicine: