Embryonic Development

By Dr. Gary Parker


Another marvelous reflection of creation is the astonishing process of embryonic development, including the way a human being develops in his or her motherís womb. But right at this point, evolutionists come up with one of their best-known arguments. They say, in effect, "Look, if youíre talking about creation, then surely the Creator must not be very good at it, or else there wouldnít be all those mistakes in human embryonic development."



shows an early stage in human development. Consider it your first "baby picture". You start off as a little round ball of unformed substance. Then gradually arms, legs, eyes, and all your other parts appear. At one month, youíre not quite as charming as youíre going to be, and here is where the evolutionist says: "Thereís no evidence of creation in the human embryo. Otherwise, why would a human being have a yolk sac like a chicken, a tail like a monkey, and gill slits like a fish. An intelligent Creator should have known that human beings do not need those things".

The marvelous development of the human embryo should make everyone a creationist, it seems to me, but evolutionists say that the so-called "gill slits, yolk sac, and tail" are useless evolutionary leftovers (vestiges) that virtually "prove" we evolved from fish, reptiles, and apes. How does a creationist respond?


Well, there they are, "gill slits, yolk sac, and a tail". Why are they there? What is a creationist going to say? The evolutionist believes these structures are there only as useless leftovers or "vestiges" of our evolutionary ancestry, reminders of the times when our ancestors were only fish, reptiles, and apes.


The concept of vestigial organs even resulted in cases of "evolutionary medical malpractice". Young children once had their healthy (and helpful, disease-fighting) tonsils removed because of the widespread belief that they were only useless vestiges. That idea actually slowed down scientific research for many years. If you believe something is a useless, non-functional leftover of evolution, then you do not bother to find out what it does. Fortunately, other scientists didnít take that view. Sure enough, studies have shown that essentially all 180 organs once listed as evolutionary vestiges have significant functions in human beings.


Take the yolk sac, for instance. In chickens, the yolk contains much of the food that the chick depends on for growth. But we, on the other hand, grow attached to our mothers, and they nourish us. Does that mean the yolk sac can be cut off from the human embryo because it isnít needed? Not at all. The so-called "yolk sac" is the source of the human embryoís first blood cells, and death would result without it!


Now here is an engineering problem for you. In the adult, you want to have the blood cells formed inside the bone marrow. That makes good sense, because the blood cells are very sensitive to radiation damage, and bone would offer them some protection. But you need blood in order to form the bone marrow that later on is going to form blood. So, where do you get the blood first? Why not use a structure similar to the yolk sac in chickens? The DNA and protein for making it are "common stock" building materials. And, since it lies conveniently outside the embryo, it can easily be discarded after it has served its temporaryóbut vitalófunction.


Notice, this is exactly what we would expect as evidence of good creative design and engineering practice. Suppose you were in the bridge-building business, and you were interviewing a couple of engineers to determine whom you wanted to hire. One person says, "Each bridge I build will be entirely different from all others". Proudly he tells you, "Each bridge will be made using different materials and different processes so that no one will ever be able to see any similarity among the bridges I build". How does that sound?


Now the next person comes in and says, "Well, in your yard I saw a supply of I-beams and various sizes of heavy bolts and cables. We can use those to span either a river or the San Francisco Bay. I can adapt the same parts and processes to meet a wide variety of needs. Youíll be able to see a theme and a variation in my bridge building, and others can see the stamp of authorship in our work." Which would you hire?


As A.E. Wilder-Smith {21} [1431] points out, we normally recognize in human engineers the principles of creative economy and variations on a theme. Thatís what we see in human embryonic development. The same kind of structure that can provide food and blood cells to a chicken embryo can be used to supply blood cells (all that is needed) for a human embryo. Rather than reflecting time and chance, adapting similar structures to a variety of needs seems to reflect good principles of creative design.


The same is true of the so-called "gill slits". In the human embryo at one month, there are wrinkles in the skin where the "throat pouches" grow out. Once in a while, one of these pouches will break through, and a child will be born with a small hole in the neck. Thatís when we find out for sure that these structures are not gill slits. If the opening were really part of a gill, if it really were a "throwback to the fish stage", then there would be blood vessels all around it, as if it were going to absorb oxygen from water as a gill does. But there is no such structure in humans of any age. We simply do not have the DNA instructions for forming gills.


Unfortunately, some babies are born with three eyes or one eye. That doesnít mean, of course, that we evolved from something with one eye or three eyes. Itís simply a mistake in the normal program for human development, and it emphasizes how perfect our design features and operation must be for normal life to continue.


The throat (or pharyngeal) grooves and pouches, falsely called "gill slits", are not mistakes in human development. They develop into absolutely essential parts of human anatomy. The first pouches form the palatine tonsils that help fight disease. The middle ear canals come from the second pouches, and the parathyroid and thymus glands come from the third and fourth. Without a thymus, we would lose "half" our immune systems. Without the parathyroids, we would be unable to regulate calcium balance and could not even survive. Another pouch, thought to be vestigial by evolutionists until just recently, becomes a gland that assists in calcium balance. Far from being useless evolutionary vestiges, then, these so-called "gill slits" are quite essential for distinctively human development.


As with "yolk sac", "gill slit" formation represents an ingenious and adaptable solution to a difficult engineering problem. How can a small, round egg cell be turned into an animal or human being with a digestive tube and various organs inside a body cavity? The answer is to have the little ball (or flat sheet in some organisms) "swallow itself", forming a tube which then "buds off" other tubes and pouches. The anterior pituitary, lungs, urinary bladder, and parts of the liver and pancreas develop in this way. In fish, gills develop from such processes, and in human beings, the ear canals, parathyroid, and thymus glands develop. Following DNA instructions in their respective egg cells, fish and human beings each use a similar process to develop their distinctive features.