Perched his wheelchair on a slippery slope, he has.
It’s a LOGARITHMIC slippery slope. Certainly life BEGINS at conception, and that is the starting point. The very first hours and days are perilous, and I’m sure some significant fraction of fertilizations never result in pregnancies, per se. That is, an embryo developing normally in the womb. I suppose one might chose this milestone as a starting part of an individual’s life journey.
So how many cells at 1 week? At least a million, I think, so isn’t the “personhood” of a fertilized cell a moot question by this point? An obfuscation of the violence done to the nascent individual at the many later and increasingly complex stages of development by the deliberate destruction of that individual?