Personal Human Life Begins with the Formation of Adult Type Hippocampus at 13th Week of Development

Abstract

One of the most controversial topics in bioethics and philosophy is the beginning of personal human life. However, an acceptable explanation has not been provided yet. The purpose of the present section is therefore to propose when a personal human life begins. Brain cortex is necessary for the personhood but there exist two different types of cortex with two different stages of development. While neocortex does not begin to get organized before 24 weeks, hippocampal cortex (a great portion of allocortex) is already formed at 13th week of development. Hippocampus is involved in the emotions and memory, and regarded as the seat of personhood. Most pyramidal cells are generated in hippocampus by the 13th week of development and, fetus has an adult type hippocampus by functional and anatomic definition at 13th week. The subsequent period is characterized by an increase in the volume of the hippocampus and its basic structure remains unchanged. The 13th week is therefore the most reasonable time at which to fix the start of personal human life. Most religious traditions hold that what makes one a person is the possession of a soul. Ensoulment seems to occur when adult type hippocampus is formed at 13th week of development. The soul may also have a component of dark matter; and they both enter the brain through the window of vomeronasal organ which is functional and has connections with the brain only during the time of ensoulment. This theory suggests that abortion and embryo research are acceptable ethically up to the point of hippocampus formation.