Human blastocysts from aggregated mononucleated cells of two or more non-viable zygote-derived embryos

This study examined the developmental capacity of aggregates of surviving mono-nucleated cells isolated from several non-viable human embryos on day 3 or day 4 after fertilization. The results clearly demonstrate that some blastomeres from non-viable embryos do indeed maintain their developmental potential and regulatory capacity to the extent of being able to contribute to a normally organized blastocyst, with as many as 90% diploid cells. Although the chimaeric nature of such blastocysts excludes them from use in therapeutic IVF, they are of particular relevance to the discussion of embryonic and trophectodermal stem cell line production.