Embryonic stem cells are derived from a blastocyst which is the stage of an embryo 5 days after fusion of an egg and a spermatozoa.
A decade ago, in order to produce such a blastocyst and derive embryonic stem cells from it, our scientists needed to retrieve eggs from a woman and collect sperm from a male and then fertilize the egg in a petri dish. Nowadays, it is no longer necessary to retrieve eggs or sperm to produce a blastocyst. Our scientists are able to produce an egg from a skin cell. They are also able to fuse such an egg with a fibroblast (skin cell) to produce an embryo.
In other words, our Embryonic stem cells are produced by transforming skin cells into embryonic stem cells following several advanced scientific steps. The blastocyst produced in the process of this transformation is a transient stage where the skin cell is fully returned to its original embryonic stage. No life is being produced or destroyed. There is only a transformation of old living cells into young and more effective ones.