agreed the term blastocyst appears to be based on a false distinction that has been drawn between the embryo proper and the embryo at an earlier stage of development sometimes the term pre embryo is used in this context however the precise stage at which an embryo can be classified as a blastocyst or a 'pre embryo' seems to involve a somewhat subjective judgement the article currently says a blastocyst is a stage of development of an embryo when it is around five days old and made up of about cells because of their highly subjective nature terms such as bastocyst and pre embryo are problematic and may be criticised for trying to dehumanize the human embryo