Looking through that collection of quotes, Ithink it would be more accurate to say "Science thinks development begins at fertilization." Which is true! Life is

Looking through that collection of quotes, Ithink it would be more accurate to say "Science thinks development begins at fertilization." Which is true! Life is a polysemous concept - by many valid definitions the gametes are alive prior to fertilization. Whether the zygote represents an individual human life is a question that "Science" definitely does not hold a monolithic opinion on. From 20 years working in a field proximal to developmental biology, my impression is that most individual scientists in relevant fields have a gradualist understanding of the emergence of individual life, involving key milestones such as implantation, gastrulation, neurulation, subsequent CNS development and "viability" (ability of the fetus to live independently of the mother's body).