I couldn't find ONE scientist in the broad field of biology, especially one in embryology, genetics, or any other field specialising in human life development, that says life in humans begins after birth. ALL the ones I found say it begins MUCH before that.
Life Begins at Fertilization with the Embryo's Conception
The Case Against Abortion: Medical Testimony
The New Atlantis » The First Fourteen Days of Human Life
ZENIT - The Facts of When Human Life Begins
"Biologic human life is defined by examining the scientific facts of human development.
This is a field where there is no controversy, no disagreement. There is only one set
of facts, only one embryology book is studied in medical school. The more scientific
knowledge of fetal development that has been learned, the more science has confirmed
that the beginning of any one human individual’s life, biologically speaking, begins
at the completion of the union of his father’s sperm and his mother’s ovum, a process
called "conception," "fertilization" or "fecundation." This is so be-cause this being,
from fertilization, is alive, human, sexed, complete and growing. "
Why Can't We Love Them Both? On Line Book by Dr. and Mrs. Willke.
http://www.westchesterinstitute.net/...life_print.pdf
So the only other issue of ANY importance is the legal one. And the legal people hinge scientific matters upon scientific expertise.
Life in humans begins before birth, and that is the consensus.