Writer and embryology expert William M Connolly describes the stages of the process of conception.
“Shortly after Fertilization:
DOUBLING: Several hours after conception, the sperm’s chromosomes are doubled inside the sperm’s nucleus, which had been within the sperm’s head, which entered the ovum. The sperm’s head dissolves after penetration of the ovum. The nucleus (pro–nucleus) remains intact. The nucleus travels across the egg’s cytoplasm toward the egg’s nucleus (pro-nucleus). The chromosomes inside the ovum’s nucleus double also.
RELEASE: When the nucleus with the male’s chromosomes nears the ovum’s nucleus, the nuclei’s walls seem to touch, almost fuse, then seem to weaken and dissolve into the fertilized egg’s cytoplasm, while the sperm’s and egg’s two sets of 23 chromosomes are released into the cytoplasm.
DOCKING: The result is four sets of 23 chromosomes in the cytoplasmic sea, not adrift, but drawn together, as if grappling hooks bound them. It is as if tethered ropes held them fast, and the great fleets of chromosomes were tugged towards each other, and pulled alongside each other. Ship to ship, as if the anchors were dropped and each ship of the fleet made its berth next to a sister ship alongside a magnificent, long, extended dock, jutting halfway across the intracellular sea. All the chromosomes are now lined up.
INTERLOCKING: Next, within the very first few hours of new human life, comes the amazing event of the interlocking of the sperm’s and egg’s chromosomes. After gracefully traversing intracellular space, avoiding impediments – sailing past Golgi apparatus, mitochondria, lysosomes, endoplasmic reticulum, the internal structures of every human cell – maintaining stability, rapidly restoring internal functioning to any genes damaged by ionizing radiation or mutagenic chemical interlopers, after the two fleets of chromosomes have met in flight in intracellular space and docked, an amazing interlocking process begins. Information is lined up. Lifelong links are firmly forged. Interlocking is completed.
DIVISION: The living processes continue, until the first human cell of this new, unique, human being becomes two cells, each with the identical genetic material of the first, each with 46 chromosomes. From now on, immediately before each cell division, which is known as a mitotic division, the 46 chromosomes are doubled. Each of the two new cells will have the same 46 chromosomes. Two cells become four, then eight, etc.
DIFFERENTATION: Mitotic divisions continue. Soon, a ball of cells is formed at the 16th cell stage; then a larger ball. Then comes differentiation, as cells begin to change detectably, to specialize, and transform gradually and gracefully, first into different tissues, ectoderm, mesoderm, endoderm, then into more specialized cells, nerve, muscle and bone, each with that unique 46 chromosomes of the original life form – the human life, the human being, the person.”