God took a rib from Adam to make Eve, but this removal of a rib from Adam did not result in all men having one less rib. There are some interesting reasons why this is true and why God chose to take a rib in the first place.
On the sixth day of creation, God created the first man. It was a special work of creation: “The Lord God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being” (Genesis 2:7). The structure and design of the human body is amazing—not to mention the soul and the fact that humans are created in the image of God (Genesis 1:27).
After creating Adam, God guided the man to the discovery that he was, in a sense, alone in the world; unlike the animals, the man had no counterpart, no equal companion: “For Adam no suitable helper was found” (Genesis 2:20). Once Adam was aware of his need, God took steps to remedy the problem. He created the woman.
How God created the woman is significant. In Genesis 2:21–22, after causing Adam to fall into a deep sleep, God took a rib out of the man and used it to form the woman. So Adam and Eve were of the same substance and were connected physically. All people are from Adam, including Eve. When God brought the woman to the man, Adam said, “This is now bone of my bones and flesh of my flesh; she shall be called ‘woman,’ for she was taken out of man” (Genesis 2:23).
Learning of God’s removal of a rib from Adam, some people assume that men today have one fewer rib than women have. It’s a wrong assumption, of course. Ribs are easily counted, and men and women have the same number of them. God made a surgical change to Adam, not a genetic change. Performing surgery does not alter one’s genetic makeup. Every descendant of Adam has the DNA encoding that produces 12 pairs of ribs—24 ribs total in the rib cage. Adam’s sons all had the same number of ribs that Adam had originally; in the same way, the son of a kidney donor will have two kidneys, not just one, and the daughter of an amputee will not be born missing a limb.
The fact that God pulled a rib out of Adam and not some other piece of his body shows God’s wisdom, planning, and foresight. Ribs regrow. All bones in the human body are able to mend themselves, but rib bone is unique in that it can regenerate. When a surgeon performs a costectomy (the removal of part or all of a rib), he or she will be careful to leave the perichondrium (the membrane surrounding the rib). The rib taken can be used for bone grafts elsewhere in the body, and in the spot of the missing rib will grow a new rib—usually within one or two months. (See Moore, K., Dalley, A., and Agur, M., Clinically Oriented Anatomy, 7th ed., Lippincott Williams & Wilkins, 2013, p. 83).
Given the rib’s ability to regenerate, we know that God did not permanently wound Adam when He took a rib from his side to make Eve. Adam did not live the rest of his life with a defect or a weak spot in his skeletal thorax. Because of God’s wonderful design, Adam lived out the rest of his days with the same number of ribs that he had been created with.