This view states that a genetically unique individual begins at conception - a fertilized egg now hosts a complete genome, making it distinct from the sex cells that came before it. Hence, from this cellular metabolic point of view, life begins when the gametes are formed from loose chemicals and ends when every bodily cell has ceased to be active. It's said that fresh (uncooked) sausages contain enough live cells to clone the pig(s) from which they came. Indeed, cellular life - and the metabolic processes performed by this - can continue to occur long after an organism can said to be dead. Both the sperm cells and the egg cells are alive prior to conception in the same sense as any other single or multicellular organism. This has profound consequences for the definition of "life" because taking this view there is, in a very real sense, no one point when life can be said to begin. A cell is either functioning or it isn't (ignoring "dormant" cells and exotic organised chemical processes for now). Bear in mind that the simple act of fertilization itself takes up to twenty hours to complete - there really is no "magic spark" that some people may like to think that happens instantaneously.įrom a metabolic perspective (i.e., cellular activity such as respiration), life is fairly easy to define. This can be a problem for people who want their world to be black and white and their morals to be absolute, and it is certainly a problem from a legal perspective, where as far as possible things need to be clear-cut and even. It may have a start where there is "no life" and an end where there "is life," but there isn't a clearly defined boundary.
Instead, the beginning of life is a process, not an event. One of the main viewpoints, and the one that possibly best reflects the reality of the situation, is that there is no one point where life begins. The reality is complex and these aren't so much five different points as five different criteria leading to five different areas of change that could be defined as "life beginning." The complexities are best demonstrated in the first category, where life doesn't really "begin" at all. This doesn't necessarily mean that there are five possible "points" to choose from and you just pick your favorite. 3 Social, cultural and governmental categoriesĬurrent scientific thinking regarding when "life" is considered to have started falls into five categories which are outlined below.
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