A New Idea Is Born

Suppose we consider a new life to be like a new invention, which under our patent laws must be both new and useful.* The novelty of a new life (identical twins aside) is self-evident in its genetic code. Inventions occur (again under our law) following conception and reduction to practice.  The two events may be connascent or sequential. Conception is the fixed and permanent idea of the invention, while reduction to practice is the embodiment of the idea. Like parenting, only an inventor can contribute to conception.

New life indeed does begin at conception, but it's not fully embodied until some indefinite point in time.
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*As for the usefulness of a newly conceived life or idea -- that requires time. The following anecdote may apply.  Sometime in the 19th century, a delegation of government dignitaries visited Michael Faraday to view his electric motors and other inventions. One said "This is all very interesting, but of what possible use are these toys?" Faraday responded: "I cannot say what use they may be, but I can confidently predict that one day you will be able to tax them."