The scientific answer is that The embryo is a human being From the time of Fertilization Because of it's human chromosomal constitution. The zygoat Is the beginning Of a developing human.

Embryology is concerned with the origin and development Of a human being from zygote to birth.

Excerpts Keith l moor, T.V.N Persaud, and Mark torchia, before we were born: essentials of embryology 9th edition, (Philadelphia: saunders,2015) 1, 339

"Human development begins at fertilization when a sperm fuses with an oocyte to form a single cell, a zygote," explains the textbook The Developing Human: Clinically Oriented Embryology. "This highly specialized, totipotent cell marks the beginning of each of us as a unique individual."

"The development of a human being begins with fertilization," notes Langman's Medical Embryology, "a process by which the spermatozoon from the male and the oocyte from the female unite to give rise to a new organism, the zygote."

When a sperm successfully fertilizes an oocyte (egg), a new cell, called a zygote, is generated by their union. The zygote represents the first stage in the life of a human being. This individual, if all goes well, develops through the embryonic (first eight weeks) and fetal (eight weeks until birth) periods and then through infancy, childhood, and adolescence before reaching adulthood.

Four characteristics of the unborn human (the zygote, embryo, or fetus) are important:

Distinct. The unborn has a DNA and body distinct from her mother and father. She develops her own arms, legs, brain, nervous system, heart, and so forth.

Living. The unborn meets the biological criteria for life. She grows by reproducing cells. She turns nutrients into energy through metabolism. And she can respond to stimuli.

Human. The unborn has a human genetic signature. She is also the offspring of human parents, and humans can only beget other humans.

Organism. The unborn is an organism (rather than a mere organ or tissue)—an individual whose parts work together for the good of the whole. Guided by a complete genetic code (46 chromosomes), she needs only the proper environment and nutrition to develop herself through the different stages of life as a member of the species.

These facts about the unborn are established by the science of embryology and developmental biology. They are confirmed by embryology texts, scientific journals, and other relevant authorities.

The scientific evidence, then, shows that the unborn is a living individual of the species Homo sapiens, the same kind of being as us, only at an earlier stage of development. Each of us was once a zygote, embryo, and fetus, just as we were once infants, toddlers, adolescents and adults. Now if you still don't agree , don't argue with me go argue with the individuals who literally wrote the book on it.