In which case the embryo is only a 'potential human life' as you there is no certainty as to how it will develop.
The complexity of your reply sort of proves my point, Burney. There are so many angles to the 'human life' definition and debate that I fail to see how anyone can come up with anything definitive. And if you can't reach an agreement as to what is or is not 'human life' I also fail to see how it can be used in the argument.
The alternative is to simply be practical and not bother with nebulous definitions.