A basic understanding of science and biology is enough to prove that it would be inaccurate to say that an embryo or a fetus is not human. At the moment of conception, the fertilized egg has a unique genetic code. It is unique from that of the mother, who contributed the egg and the father who contributed the sperm. The genetic information contained in the DNA of this new individual at conception is “equivalent to a library of one thousand volumes, or six hundred thousand printed pages with five hundred words on a page”. (Alcorn, 65)
Whether it is an embryo or a fetus, a human - even at its earliest stage - is anything but a simple blob of tissue or clump of cells. In fact, before many women realize they are pregnant, the embryo has formed (at varying stages of development) every internal organ that an adult human has.
As early as 5 weeks 5 days from the first day of her LMP (last menstrual period) a woman can come to the Alight Center to have an ultrasound. At this point the embryo is only 3 weeks 5 days old and a heartbeat can be detected. At an incredible rate an embryo grows according to the directions found in that very complex genetic code that is created at fertilization. Here is a simple timeline of the speed and specificity in design of each individual human in the womb.
This is all before 8 weeks from fertilization, when the unborn is no longer considered an embryo, but is now called a fetus.
Alcorn, Randy (2000). ProLife Answers to ProChoice Arguments. Colorado: Multnoma Books.