Hmmm ... it's beginning to seem like it really makes precious little difference whether or not the the 'holy spirit' actually exists.
What is it about implantation that makes it serve as a significant moment? The Mayo Clinic reports that at least 15-20% of all pregnancies naturally end in spontaneous abortion. Most of these miscarriages occur before the end of the first trimester, but many will occur after implantation. So, implantation doesn't seem like a good marker of viability.
Perhaps it is the kind of development of the blastocyst that begins on the ninth day after the fertilization of an egg that you find important?
“Why is it that we rejoice at a birth and grieve at a funeral? It is because we are not the person involved.” ~ Mark Twain