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When does human life begin?

Thank you for coming back to read my blog!

Today, I am discussing a controversial topic that many groups of society approach from different point of views: when does life begin?

First and foremost, I would like to clarify that I am not going to approach this question from the religious point of view. I want to provide some scientific evidence that might help you understand the biological processes that an embryo, fetus, and newborn go through. I will leave the topic of religion to you, to your own believes and how your roots have shaped your thoughts.

After conception (the union of he sperm and the egg), there are many different stages and that take course to form a fetus and a newborn. Some of those stages have been particularly associated with the beginning of life. The following table, in chronological order, encompasses most of those stages.

Time After Conception



Week 0 Conception Union of gametes to form a new human being
Week 1 Gastrulation Embryo forms germ layers and first cellular differentiation happens
Week 1-2 Implantation Embryo attaches to the uterus and the placenta starts developing
Week 5-6 Heart beating Heart starts beating at a regular rhythm
Week 26-27 Fully formed nervous system Brain, spinal cord and nerves produce impulses and control movement
Week 39-42 Fetus is fully mature Fetus is able to survive without the mother
After birth Newborn breaths Newborn is able to survive outside of the womb


Moreover, there are other scientists that believe that there is not a specific time when life begins. Instead, life takes form in a dynamic way and human life just does not begin, as most religious points of view believe. I however, think that as scientists, we need to provide answers to this question to inform people on how humans develop.

At this point in time, I believe that human life begins at the gastrulation stage. It is in this stage of development when cells start organizing and differentiating to give rise to organs and systems. Also, the cells here start their development in a more coordinated and organized manner.  A gastrulated embryo has the potential to move forward to develop a new being. The following picture shows how cells start organizing in the embryo.


My position on this topic might change in the future as I learn and understand better the processes influencing embryonic and fetal development.

Welcome to my Blog… What is it about?

My plan for this blog is to share information and my thoughts on subjects related to human and animal developmental biology. I will address these topics from the physiological standpoint; always trying to tie the content to environmental, bioethical, and well being issues. In this occasion I am introducing broadly the concept of developmental biology and discuss my main interest within this science.

First and foremost, developmental biology could be broadly defined as the branch of biological sciences that studies the processes (chemical, molecular, and physiological), that bring two reproductive cells (gametes) to combine and produce an embryo to progressively generate structures such as specialized cells, organs, systems, and fully mature organisms.

Early in my veterinary studies, reproductive sciences sparked my interest in understanding how gametes can produce an offspring. It is a fascinating process that many people consider a miracle due to the complexity of the events. However, I want to discuss the most important steps to illustrate the greatest adaptations that animals have acquired to propagate in their environments.  My greatest interest in this science lays in understanding the communication between mammalian embryos, in early stages, and the maternal environment to begin the implantation process. More importantly, my ultimate goal is to understand the physiology and environmental effects in those developmental steps to aid animal conservation. Nevertheless, I will be discussing some other important aspects that occur throughout development in mammal and non-mammalian species.

Thank you for reading and I will be posting again soon!