When does Human Life Begin





Alex Tang



Spiritual writing


Nurturing/ Teaching Courses

Engaging Culture

Spiritual Formation Institute

My Notebook

My blogs

Books Recommendation



Medical notes

Medical Students /Paediatric notes




























When does Human Life Begin?

Dr Alex Tang

In Genesis, the first book of the Christian Bible, it is recorded that God created humans out of the dust of the earth. He made the first man, named Adam and breathed life into him (Genesis 2:7). This implied a process. First, God formed Adam out of the dust of the ground. He only became a living being after God breathed the breath of life into him. Then God created woman, Eve, out of a rib from Adam, the first recorded case of plastic and reconstructive surgery (Genesis 2:22). In the case of Adam and Eve, we know when life began and when they became human beings and persons. But the Bible does not give further information on when the rest of humankind become human beings and persons. The Bible records that Adam had sexual intercourse with Eve and Eve became pregnant. After a term of pregnancy, Cain was born. Nowhere in the Bible is it stated when human life begins.

This fact is important when we discuss bioethical issues of abortion, reproductive technologies, cloning and stem cell research. Central to many of the arguments and disagreements concerning these issues is the question, “When does human life begin?” The debate has divided Christians from the various traditions (Roman Catholic, Orthodox and Protestant) because of the silence of the Bible on this important piece of information. It also makes it difficult to dialogue with people from other traditions and beliefs. It is especially relevant as science and technology intrude into our sexual reproductive processes.

The Biology of Sex

During a woman’s reproductive period from puberty (menarche) to menopause, she produces a few hundred thousands eggs or ovum which are released from her ovaries into her fallopian tubes during the fertile phase of her monthly menstruate cycle. During sexual intercourse, a male ejaculates millions of spermatozoa into a woman’s vagina. These race upwards into the fallopian tubes. There these millions of spermatozoa meet a single egg. Fertilisation is said to have taken place when a single spermatozoa penetrates into the egg or ovum. Once a spermatozoon has penetrated into an ovum, a barrier is immediately built up to prevent other spermatozoa from entering. In the egg, there is fusing of the DNA genetic materials resulting in the forming of an embryo or fertilised ovum or blastomere. This begins to divide by a process of mitosis where it begins to split down the middle and two identical cells are formed. This process is replicated continuously. In the meantime, the embryo moves down the fallopian tubes into the uterus. It takes about four to seven days before it reaches the uterus. By then, it will compose of about 100 cells and is known as a blastocyte or ‘pre-implantation embryo’. This blastocyte has to implant in the uterine wall and produce a secretion, human chorionic gonadotrophin (hCG) which makes the uterine walls favourable to further growth and prevent menstruation. Failure to implant in the uterine wall will result in the blastocyte being washed out of the uterus and die. It is estimated that 40 to 70 percent of all ‘pre-implantation embryos’ are discarded without the woman being aware of it.

When does Human Life Begin?

The Roman Catholic Church, the Orthodox Church and some of the Protestant denominations regard conception as the point when the spermatozoa penetrates the ovum and fertilises it. To them, conception is when human life begins. Conception is when the soul enters the cell or ensoulment has occurred. The philosopher Aristotle believed that at conception the future child is endowed with a principle of only vegetative life. This is exchanged after a few days for an animal soul. The animal soul is succeeded by a rational soul much later. His followers taught that a male child receives his rational soul on the fortieth day. The female child receives her rational soul on the eightieth day. This belief was widely accepted by the ancient world for many centuries. In the fourth century, Gregory of Nyssa, who was well educated in Greek teaching, advocated the view that at the time of conception, the embryo is given a life principle (soul) and begins to live a distinct individual life. However Thomas Aquinas, the great Dominican theologian reverted to the Aristotle teaching that a male was given a soul after 40 days and the female after 80 days. This was accepted by the church and later became widely accepted as a church tradition until 1875. In 1875, the German embryologist Oskar Hertwig discovered that the important event in fertilization was the fusion of the spermatozoa and the ovum (egg). That year, the Sacred Congregation for the Doctrine of Faith in Rome declared that human being exist and became ‘ensouled’ at the moment of spermatozoa entering the ovum. In 1987, they modified their view by declaring that human life begins not at the moment of penetration of the ovum by the spermatozoa but at the moment of the fusion of the male and female genetic materials (nuclei). Modern science has discovered that there is a time lapse of 22 hours between the moment the spermatozoa penetrate the ovum wall and the fusion of the genetic materials.

The late Pope John Paul II reaffirmed the Roman Catholic tradition that life begins at conception when he wrote: “When a unique set of human genetic instruction is present, a person is present.” In his attempt to modernise a church tradition, the late pope implied that the presence of a complete set of human DNA makes a cell a human person. To modern scientists, it may not make sense. They may retort that all our skin cells have complete sets of human DNA and we lose millions of skin cells a day! Is each cell then a person? Having a complete set of human DNA may not make a person as in the case of a teratoma. A teratoma is a fertilised ovum mutated into a tumour. There are differentiations of tissues in a teratoma though in a chaotic manner. When we cut open a teratoma, we may find hair, mixed with tooth and other organs but a human being was never formed. All the genetic information was present but the development went haywire. Another point to be considered is that 40 to 70 percent of fertilised eggs die when they fail to implant in the womb. If the presence of a complete set of DNA defines a human person, then one would have to say that the majority of human beings were never born or lived no longer than a week.

Professor John Guillebaud from the University of College, London has suggested that conception be seen as a process. He believes conception has two components: fertilisation and implantation. Fertilisation without implantation has zero survival rate. Fertilisation and implantation has about 80 percent chance of making it to term. Hence Professor Guillebaud would consider conception to have taken place only when a fertilised ovum implants in a uterine wall. Conception, according to him, would not have taken place if the spermatozoa penetrated the ovum and fertilised it but was not implanted, as in spontaneous abortions or fertilisation in a test tube. On the other hand, Professor Ramsey, a noted Protestant ethicist, believes a zygote is a human being i.e. human life begins at conception. Professor Ramsey did not go into the technical details.

Fourteen Days

Many in the scientific community believe that human life begins 14 days after conception. Implantation begins at day five and completes by day nine. By day 14, the cells of the embryo begins to specialise so that the embryo has a top, bottom, front and back. A primitive streak is formed which will develop into the spinal cord and nervous system. Other cells begin to separate into foetus, placenta and other supportive tissues.

At 14 days, the possibility of twinning recedes. Twins are formed when the embryo splits into two, each with equal and identical genetic materials. Both embryos continue their development. These are identical twins because they are from one embryo. They share one placenta. Non-identical twins happen when two ova are fertilised and the two embryos are implanted at almost the same time. They develop independently of each other. Triplets, quadruplets and so forth are similarly formed.

Some would regard this as an important fact. If one were thinking in terms of souls, then would an embryo that is destined to split and become twins be given two souls at conception? Could two souls coexist in one embryo? If at conception, one soul were given, what would happen when the embryo splits into two when twinning occurs? Another observation is that prior to 14 days, two embryos can fuse and subsequently develop normally but with four sets of genetic information.

In the United Kingdom, an ethics committee led by Dame Mary Warnock, a philosopher came to the conclusion that it is not unethical to create and experiment on embryos as long as it does not occur fourteen days after fertilisation. The Warnock Committee’s recommendation served as the basis of The Human Fertilisation and Embryology Authority Act passed in the United Kingdom in 1990. This Act governs IVF (In Vitro Fertilisation) and the treatment of embryos. Experimentation of embryos was allowed under the Act until fourteen days after fertilisation.

The 14-day mark is the choice of the Embryo Research Panel of the National Institute of Health (1994) in the USA and of the Donaldson Report in UK. Many other research institutes also follow similar definitions that human life begins at 14 days with the formation of the primitive streak and the possibility of twinning recedes.

Twenty Eight Days

The formation of all body systems and organs is complete after 28 days. The embryo is about two mm long. During subsequent growth, these organs will increase in size and functions. The embryo can now be considered ‘formed’. A human body or nephesh may be said to be present. In the early and medieval church, the consensus among theologians was that God would give a soul at the point when the body is fully ‘formed’ at the womb. This is known as soul creation. Another school of thought called traducianism taught that a soul is inherited from one’s parents and will be fully formed when there is a formed body. One can only be a human being if one has a body and a soul. This is obviously different from the beliefs of the early Church Fathers that a life principle (soul) is given at conception. Both soul creation and traducianism reason that one needs to have a body to have a soul. The distinction is between ‘formed’ and ‘unformed’. Those who taught this include Lactanius, Jerome, Augustine, Cyril of Alexandria and Thomas Aquinas.

Forty Days

Aristotle wrote that the male embryo develops a human soul about 40 days after conception, whereas a female embryo acquires its soul 80 days after conception. One author has suggested that the early church was influenced by this ‘delayed ensoulment’ principle and allowed abortion up to 90 days.

At 40 days, primitive undeveloped brain waves can be detected. High resolution ultrasound done on the foetus at this stage shows incredible details—the foetus begins to look like a baby. In the Jewish rabbinic understanding of the Talmud and subsequent teachings, a developing foetus before 40 days is ‘like water’. It is only worthy of consideration after 40 days.

Twenty Four Weeks

About 24 weeks, the foetus becomes viable. This means that if it was delivered prematurely, it can survive with the help of modern medical care. The World Health Organization (WHO) defined abortion as any product of conception delivered before 28 weeks. However, nowadays it is routine to be able to save babies born prematurely at 24 weeks. Some medical ethicists use viability as a measure of being human.

Twenty Six Weeks and Later

There is now viability and foetal higher function becomes operational. Brain wave patterns show waking and sleeping stages. To some people, this self-awareness is what makes a human being. Self-awareness is one of the important criterions of personhood. Carl Sagan believed that the ability to think is what makes us human.

First Breath at Birth

The Jewish rabbinic commentary regards the foetus to be part of the mother’s body and it is only at the moment when the head or the greater part of the breech is delivered that the foetus becomes an individual. But it continues to be regarded as a non-souled entity until after 30 days. Jewish children are not named or admitted to the community until after the eighth day and for those who die in the perinatal period (30 days), the rituals of death are not necessary.

Human Life and the Bible

The Bible did not give an answer to this most basic of question, “When does human life begins?” Attempts have been made by various scholars to cite evidence that God consider the fetus to be fully human by referring to Psalm 139, Job 3:11, Jeremiah 1:5 and Luke 1:39-44.

John Stott made an ingenious argument by using Psalm 139. Firstly, using verse 14, ‘for you created my inmost being; you knit me together in my mother’s womb’, he concluded that the psalmist is already aware at his conception – creation. Secondly, in verse 1 ‘ you have searched me’ (the past), verse 2-3, ‘ you know when I sit and when I rise ..’ (the present) and verse 10,’your hand will guide me, your right hand will hold me fast..’(the future).There is continuity. And thirdly, the whole Psalm 139 spoke of communion between God and the psalmist. John Stott concluded that these three words (creation, continuity, communion) gave us the perspective to see that the fetus is already a human life, though not yet mature have the potential of growing into the fullness of humanity. The point he made was that the beginning of human life is found in the pre-natal period and there is continuity from life before and life after birth. One must be aware of making inferences from a poetic genre. The Psalmist was a grown man making observation about his life. This is the perspective of a person looking backwards in time.

"Why did I not perish at birth, and die as I came from the womb?” Job 3:11 (NIV). Job 3:11 is a metaphor. It sheds no light on whatsoever on the status of the foetus Job. Again it is a retro perspective view as it is the adult Job contemplating his circumstances.

"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." Jeremiah 1:5 (NIV). Jeremiah 1:5 is more about God calling of Jeremiah to be his prophet rather than a statement of when Jeremiah became a human being.

Luke 1:39-44 is about when Mary and Elizabeth met, both being pregnant. Elizabeth’s baby (John the Baptist) ‘leaped in her womb’ in respond to the presence of Mary’s baby (Jesus). The case was made here that Luke uses the same word brephos of an unborn child (1:41,44) as he later uses of a new-born baby (2:12,16) and of the little ones whom people brought to Jesus to be blessed by him (18:15). It is difficult to conceive of a principle by one Greek word. Luke who was often careful of his words classifies them all as children. Being a medical doctor, Luke must be aware of ‘quickening’ or when the unborn child makes his or her first movement in the womb. The emphasis on this passage is on the reaction of the unborn John the Baptist to the unborn Jesus.

As we have seen, these often quoted passages did not address the question, “When does human life begins?” When proper exegesis has been done, we can only conclude that while dealing with born and unborn child, the emphasis is on the sovereignty of God and His interactions with human beings that were born and had grew up to adulthood.

Human Life and Personhood

In recent years, the discussion on “when does human life begin?” has changed to “when does a person become a person?” There are a few ethicists who think that having the human genetic code and looking like a human being does not guarantee that the entity is human. Being human also involves personhood. Mary Anne Warren’s criteria for a person are consciousness, reasoning, self-motivated activity, capacity to communicate and self-awareness. A newborn baby does not seem to exhibit all of these characteristics. Peter Singer, Ira W. DeCamp Professor of Bioethics, University Center for Human Values, Princeton University, believes that personhood comes weeks after birth. A fertilised ovum or a developing embryo in the uterus is not a person until it becomes self-aware. According to Peter Singer, self-awareness is an important criterion for personhood and this comes long after birth. More about personhood when we discuss abortion in the next chapter.


It is obvious there is no general consensus about when human life begins among the Christian community. There is also no consensus about when personhood begins or even whether personhood is a prerequisite of being human, or when ensoulment or when the soul enters an embryo. Firstly, it must be noted that the various options discussed above are based on learned speculation. Speculations which were widely accepted became church tradition. It must also be noted that while these church teachings draw on the teaching of the Bible, the Bible does not specify when exactly human life begins except for Adam and Eve. Here we must be clear in our thinking which is theology and which is church tradition. We also need to differentiate these from absolute truth. Theology is the study and knowledge of God’s revelation of himself in the Bible and in his creation. We are finite in our understanding and are limited by culture, time and language. Hence our theology is an approximation but never the absolute truth. Only God has the absolute truth. But as we grow in our understanding and develop new scholarship tools, we begin to understand more. That is why theology is constantly developing as we understand more and more of the absolute truth. Some revelations of God of God are certain and unchangeable. One example is the Trinity: Three Persons yet one. No amount of development of theology can add another person to the Trinity. Another is that Jesus Christ is fully God yet also fully human. Other areas of theology are formed and informed by our times and culture. As we have noted above, great Church theologians like Augustine is neo-platonic in his approach while Thomas Aquinas lean towards Aristotle’s teachings. Church traditions are often human formulations made to meet the needs of their times and politics. But usually once implemented, it becomes inflexible and believers are required to follow unquestioningly. Tradition may or may not be based on absolute truth.

Secondly, there must be room for differences of opinions since the Bible does not specify the time of the beginning of human life. As our knowledge of human embryology improves, we learn more of the formation of the wonderful human body. We must realise that earlier church speculations were based on the knowledge of human embryology of their time. One cannot help but wonder what the early Church Fathers would do if they knew that the human foetus develops gills, tail and other characteristics similar to other animals before developing into a form that we are used to.

A Christian Medical Fellowship survey published in 1996 showed that of the 2,580 Christians doctors who responded, only 36 percent believed that human life had ‘full value’ at the time of fertilisation. However for the 8-week old foetus, the figure had risen to 85 percent. This survey clearly showed that practitioners, people who are engaged in marketplace ministries, often have different perception of the issues involved compared with those from theological institutions. It must be noted is that the survey was about abortion and how Christian doctors perceive issues involved.

We must have the true humility to acknowledge that there are limits to human knowing. In this case, we just do not know when human life begins. The theologians may argue from Scripture but they must acknowledge that these few passages we have alluded to do not actually tell us when human life begins. Empirical scientific data or philosophy with a working knowledge of embryology may arrive at a 14 days guideline. Judaism has another time frame. The simple truth is that we just do not know. When a human life begins remains and will always be one of the Mysteries of God.

Thirdly, in areas where the Bible is non-specific, the church has always gravitated to a principle of least harm done. This is a notable principle and I think this is the most relevant in our argument. If we really do not know, then we should aggravate towards a stand that will cause the least harm. I am sure most people will agree with this. The fundamental rule of medicine is “first do no harm”. Therefore the stand that will do the least harm is that human life begins at conception.

Finally, our decision on when human life begins has a decisive effect on how we deal with the issues of abortion, use of reproductive technologies, cloning and stem cells research. While the Bible is silent on when human life begins, it has given us a clear mandate of loving our neighbours and helping the weak and sick. Maybe that is precisely why the Bible is silent on when human life begins. God may want us to use our judgment on how we can love our neighbours and help the weak and the sick. He knows that as our scientific data increase, we need to evaluate our works of charity instead of being fixed by a mould. The prophet Micah wrote, “He has showed you, O man, what is good. And what does the Lord require of you? To act justly and to love mercy and to walk humbly with your God.”(Micah 6:8). Our decision on when human life begins must be based on available facts, cause least harm, helpful to our neighbours, help the weak and most of all, we must be humble. All our bioethical decisions must be made in humility before our Creator God who has given us the power to be ‘co-creator’ with him. We recognise God as the Creator who created ex-nihilo. But we are also called to be ‘co-creator’ with him as we ‘create’ new things from materials in his creation. Computers, mobile phones and television did not exist in the Garden of Eden but was ‘created’ by us using the natural physical laws and principles of God’s creation.

                                                                                                                                                                           Soli Deo Gloria

|posted 10 June 2006|

|updated 22 Feb 2010|


"treat, heal, and comfort always"

 "spiritual forming disciples of Jesus Christ with informed minds, hearts on fire and contemplative in actions"  


Website Articles Spiritual Writings Nurture/ Courses Engaging Culture Medical Interests Social















  Creative Commons License

Except where otherwise noted, content on this site is
licensed under a
Creative Commons Attribution 3.0 License

© 2006-2018 Alex Tang