Beginning of Human Personhood - Biological Markers

Biological Markers

One of the possible basic requirements for personhood is individuality, which entails differentiation between the person and its parents. Biology offers a number of stages in the life cycle that have been seen as candidates for personhood:

• fertilization, the fusing of the gametes to form a zygote
• implantation, the start of pregnancy, occurring about a week after fertilization
• segmentation, after twinning is no longer possible.
• when the heart begins to beat
• neuromaturation, when the central nervous system of fetus is neurobiologically "mature"
  • "brain birth" concepts (compare with brain death):
    • at the first appearance of brain waves in lower brain (brain stem) - 6-8 weeks of gestation (paralleling ′′whole brain death′′)
    • at the first appearance of brain waves in higher brain (cerebral cortex) - 22-24 weeks of gestation (paralleling ′′higher brain death′′)
• the time of fetal movement, or "quickening"
• when the fetus is first capable of feeling pain
• when it can be established that the fetus is capable of cognition, or neonatal perception
• fetal viability
• birth
• post-birth development stages