Unfortunately, from conception and on into the earliest stages, there are two separate threads of DNA inside the fertilized ovum: one thread belonging to the father, the other to the mother.  It seems forced to call this the beginning of a continuum. The continuum does not begin until a decisive biological moment when a divided creature suddenly becomes a being with its own unique DNA. I mean to Google this to get my facts straight, but I think this is accurate. I do not believe we can talk about a human person until we have that unique individual with its own unique DNA.