Start of Human life
Philosophical and Religious arguments are based on principles and concepts beyond physical evidence:
Consciousness: the status of personhood is applied at the first point of consciousness or awareness.
Ensoulment: the status of personhood is deemed appropriate when the soul enters the body.
Continuity: life must begin when the potential life as an individual entity is recognisable, which is the zygote at conception.
Relational factors: all arguments based upon the meaning of words or what the philosopher Peter Vardy calls Relational Factors. That is, there are different interpretations of the same words. Until accurate definitions of key terms are agreed the stage at which personhood is awarded can never be universal.