I have learned from my earliest medical education that human life begins at the time of conception.... I submit that human life is present throughout this entire sequence from conception to adulthood and that any interruption at any point throughout this time constitutes a termination of human life....

I am no more prepared to say that these early stages represent an incomplete human being than I would be to say that the child prior to the dramatic effects of puberty...is not a human being. This is human life at every stage.¹

…after fertilization has taken place a new human being has come into being.... Each individual has a very neat beginning, at conception.²

By all the criteria of modern molecular biology, life is present from the moment of conception.³

Actually, we do know when human life begins. It begins at conception. A sperm, with just its 23 chromosomes, is not a human being; nor is an ovum, with its 23 chromosomes. But when they unite into one entity with 46 chromosomes, the result is a human being. This is a medical fact. Genetically, the fertilized ovum is a human being, with its own lifelong, characteristic code and identity. From this point on, it is simply a matter of its growth, not of its kind.⁴

It is incorrect to say that biological data cannot be decisive.... It is scientifically correct to say that an individual human life begins at conception.... Our laws, one function of which is to help preserve the lives of our people, should be based on accurate scientific data.⁵

The changes occurring between implantation, a six-week embryo, a six-month fetus, a one-week-old child, or a mature adult are merely stages of development and maturation. The majority of our group could find no point in time between the union of sperm and egg, or at least the blastocyst stage, and the birth of the infant at which point we could say that this was not a human life.⁶

First of all, if it is not human before it is born, then what is it? It is not a mineral or a vegetable. It is not an animal such as a dog or a monkey. In fact, it is not an animal at all; it is a human being. Cows give birth to cows; horses give birth to horses. No medical person has any difficulty identifying an unborn dog as a dog, or an unborn pig as a pig. Why should there be any question about an unborn human?⁷

First, though appearance can be helpful in determining what is or is not fully human, it is not a sufficient or a necessary condition for doing so. After all, mannequins in stores resemble humans and they are not even remotely human. On the other hand, some human oddities – such as the elephant man or the bearded lady,… are nonetheless fully human. The reason why we believe that the bearded lady and the elephant man are fully human and the mannequin is not is because the former are functioning individual organisms that genetically belong to the species Homo sapiens. The latter is an inanimate object.

Second, Davis points out that "this objection assumes that personhood presupposes a postnatal form. A little reflection, however, will show that the concept of a ‘human form’ is a dynamic and not a static one. Each of us, during normal growth and development, exhibits a long succession of different outward forms." An early embryo, though not looking like a newborn, does look exactly like a human ought to look at this stage of his or her development. Thus, to insist that "the appearance of an 80-year-old adult differs greatly from that of a newborn child, and yet we speak without hesitation of both as persons. In both cases, we have learned to recognize the physical appearances associated with those development stages as normal expressions of human personhood."⁸

Let’s take, for example, two babies born in Austria a number of years ago. One was a healthy boy for which the mother was glad. The other was a girl. She had Downs Syndrome, and her mother was grieved. Nevertheless, this mother loved the little girl and taught her to care for herself. One day the mother had a stroke, which left her helpless. Her retarded daughter took over her care for the rest of her life. The boy that day also grew up. The whole world later heard of him. His name was Adolf Hitler. Now, which of these babies would the abortionist have done away with?⁹]

Viability is the time at which the unborn human can live outside her mother’s womb. Some have argued that prior to this time, since the unborn cannot survive independent of her mother, she is not a completely independent human life and hence not fully human.

Bioethicist Andrew Varga points out a number of problems with the viability criterion.

First, "how does viability transform the nature of the fetus so that the non-human being then turns into a human being?" That is to say, viability is a measure of the sophistication of our neonatal life-support systems. Humanity remains the same, but viability changes. Viability measures medical technology, not one’s humanity.

Second, "is viability not just an extrinsic criterion imposed upon the fetus by some members of society who simply declare that the fetus will be accepted at that moment as a human being?"[10] In other words, the viability criterion seems to be arbitrary and not applicable to the question of whether the unborn is fully human, since it relates more to the location and dependency of the unborn than to any essential change in her state of being. This criterion only tells us when certain members of our society want to accept the humanity of the unborn.

And third, "the time of viability cannot be determined precisely, and this fact would create great practical problems for those who hold this opinion."¹¹

Long ago, medical professionals changed the accepted starting point of pregnancy from fertilization to implantation.  This redefinition was political in nature and done to further the acceptance of abortifacient contraception.   

Abortion rights groups are using this redefinition to bolster their claim that birth control and emergency contraception are not abortifacients.

However, this politically motivated redefining of pregnancy is not accepted by all physicians nor all dictionaries.  Many doctors and dictionaries describe pregnancy as beginning at conception, and define conception as fertilization.  In fact, Stedman’s Medical Dictionary, a well respected and recognized publication, defines pregnancy as beginning at conception, not implantation.  According to this definition, drugs which prevent implantation do indeed cause an abortion!¹²

Human development begins after the union of male and female gametes or germ cells during a process known as fertilization (conception).

Fertilization is a sequence of events that begins with the contact of a sperm (spermatozoon) with a secondary oocyte (ovum) and ends with the fusion of their pronuclei (the haploid nuclei of the sperm and ovum) and the mingling of their chromosomes to form a new cell. This fertilized ovum, known as a zygote, is a large diploid cell that is the beginning, or primordium, of a human being.¹³

Virtually every human embryologist and every major textbook of Human Embryology states that fertilization marks the beginning of the life of the new individual human being.

The reason why this is true is the following:

from the moment when the sperm makes contact with the oocyte, under conditions we have come to understand and describe as normal, all subsequent development to birth of a living newborn is a fait accompli. That is to say, after that initial contact of spermatozoon and oocyte there is no subsequent moment or stage which is held in arbitration or abeyance by the mother, or the embryo or fetus. Nor is a second contribution, a signal or trigger, needed from the male in order to continue and complete development to birth. Human development is a continuum in which so - called stages overlap and blend one into another. Indeed, all of life is contained within a time continuum. Thus, the beginning of a new life is exacted by the beginning of fertilization, the reproductive event which is the essence of life.¹⁴

[quote] The development of a human begins with fertilization, 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.¹⁵

It is often claimed by abortion-rights advocates that "no one knows when life begins." Right away it must be observed that this formulation is imprecise. For no one who knows anything about prenatal development seriously doubts that individual biological human life is present from conception [by which he means what other are calling fertilization]. …

If it is true that we don’t know when full humanness begins, this is an excellent reason not to kill the unborn, since we may be killing a human entity who has a full right to life. If game hunters shot at rustling bushes with this same philosophical mind-set, the National Rifle Association’s membership would become severely depleted. Ignorance of a being’s status is certainly not justification for killing it.¹⁶

Human embryologist Bruce Carlson, in his 1994 textbook: "Human Embryology and Developmental Biology", states in his opening sentence: "Human pregnancy begins with the fusion of the egg and the sperm…."¹⁷ This is so because the concern of Human Embryology is the human embryo whether it be in the fallopian tube, uterus, ectopically placed or in a petri dish. Additionally, for a pregnant woman, the expected time of delivery, fertilization age, time of gestation, or, the period of confinement is always calculated so that the time of pregnancy begins at fertilization.¹⁸

Know that the LORD Himself is God; it is He who has made us, and not we ourselves; we are His people and the sheep of His pasture. (Psa. 100:3)

Thus says the LORD, your Redeemer, and the One who formed you from the womb, "I, the LORD, am the maker of all things, stretching out the heavens by Myself, and spreading out the earth all alone…." (Isa. 44:24)

But now, O LORD, Thou art our Father, we are the clay, and Thou our potter; and all of us are the work of Thy hand. (Isa. 64:8)

Before I formed you in the womb I knew you, before you were born I set you apart; I appointed you as a prophet to the nations. (Jer. 1:5)

But when He who had set me apart before I was born, and had called me through His grace…. (Gal. 1:15)

So the LORD said to him, "Who has made man’s mouth? Or who makes the mute, the deaf, the seeing, or the blind? Have not I, the LORD?" (Ex. 4:11)

Behold, children are a gift of the LORD; the fruit of the womb is a reward. (Psa. 127:3)

Or do you not know that your body is a temple of the Holy Spirit who is in you, whom you have from God, and that you are not your own? For you have been bought with a price: therefore glorify God in your body. (1 Cor. 6:19-20)

1 Randy Alcorn, "Scientists Attest To Life Beginning At Conception," http://www.epm.org/articles/life_conception.html

2 Ibid.

3 Ibid.

4 Dr. Norman L. Geisler, "Common-Sense Answers to Arguments For Abortion," http://www.leaderu.com/orgs/tul/faq.html

5 Randy Alcorn, "Scientists Attest To Life Beginning At Conception," http://www.epm.org/articles/life_conception.html, emphasis added.

6 John C. Willke, Abortion Questions and Answers (Cincinnati, OH: Hayes Publishing, 1988), p. 42, from Randy Alcorn, "Scientists Attest To Life Beginning At Conception," http://www.epm.org/articles/life_conception.html

7 Dr. Norman L. Geisler, "Common-Sense Answers to Arguments For Abortion,"
http://www.leaderu.com/orgs/tul/faq.html

8 Francis J. Beckwith, "Is the Unborn Less Than Human?" © 1991, 1998, Christian Research Institute. http://www.christiananswers.net/q-sum/q-life000.html, quoting John Jefferson Davis, Abortion and the Christian (Phillipsburg, NJ: Presbyterian and Reformed, 1984), p. 58.

9 Dr. Norman L. Geisler, "Common-Sense Answers to Arguments For Abortion," http://www.leaderu.com/orgs/tul/faq.html

10 Andrew Varga, The Main Issues in Bioethics, Second edition (New York: Paulist Press, 1984), pp. 62-63, in Francis J. Beckwith, "Is the Unborn Less Than Human?" © 1991, 1998, Christian Research Institute. http://www.christiananswers.net/q-sum/q-life000.html, quoting John Jefferson Davis, Abortion and the Christian (Phillipsburg, NJ: Presbyterian and Reformed, 1984), p. 58.

11 Ibid., p. 63.

12 "Plan B Facts," http://www.planbfacts.com/

13 Keith L. Moore, Essentials of Human Embryology. Toronto: B.C. Decker Inc, 1988, p.2

14 C. Ward Kischer, "When Does Human Life Begin? The Final Answer: A human embryologist speaks out about socio-legal issues involving the human embryo." http://www.lifeissues.net/writers/kisc/kisc_04whenlifebegins2.html

15 T. W. Sadler, Langman’s Medical Embryology. 7th edition. Baltimore: Williams & Wilkins 1995, p. 3

16 Francis J. Beckwith, "Is the Unborn Less Than Human?" © 1991, 1998, Christian Research Institute. http://www.christiananswers.net/q-sum/q-life000.html

17 Carlson, Bruce. 1994. Human Embryology, p.1. Churchill - Livingston, New York.