About a billion years ago, scattered particles on Earth coalesced into life forms that emerged briefly and perished just as quickly. This cycle repeated across the planet, with diverse life entities sprouting and vanishing in rapid succession. Over millions of years, the interval between birth and death gradually lengthened, and evolving beings developed what I call the “Bifurcating Force,” the primal ability to self-replicate. Unicellular life eventually progressed into multicellular life, primarily through cellular bifurcation. In this early process, a tiny protrusion formed on the surface of microorganisms, grew, and ultimately detached to become a new being. This daughter entity then repeated the cycle. Yet as geographical and atmospheric conditions shifted, the protrusion slowly internalized within multicellular organisms. Even so, this once-external swelling, now larger and sheltered, still emerged with difficulty as a single mature cell.
As evolution advanced, these small creatures developed an Internal Passage. The outward-growing lump transformed into an oval structure at its base that served as nourishment. This lump became the egg, maturing within the body and eventually being expelled through the internal passage, fully formed and enclosed in an oval shell. Within the egg, its fluid grew enriched and energized through subtle chemical reactions. After hatching, new life emerged, fed, and multiplied by the same method.
If we call this internal passage the vaginal passage, the term is fitting. Species with a well-developed vaginal passage generally succeeded in producing offspring, whereas those lacking or bearing malformed passages could not replicate and died without progeny. These non-reproductive beings, I term the “incapables.” Among both the capables and incapables, many oviparous species began developing breast glands; however, only the capables, those with more intricate wombs, displayed early signs of viviparity.
Yet evolution held a promise for the incapacitated. Amid shifting conditions, they gradually developed a unique reproductive system, which I shall call the penis, accompanied by auxiliary organs. This development, too, was shaped by the Bifurcating Force inherent within them. Interaction and union differed from creature to creature, but encounters between complementary organs awakened new hormones. These chemical stirrings completed the development of sexual glands in both parties, activating a complex system of auxiliary components. Friction between the complementary organs filled the beings with intense pleasure, ultimately giving rise to sexual instinct as an additional survival mechanism. Thus, the newly formed group, equipped with a penis and scrotum, and the ancestral group, bearing the early vaginal passage (with the full vagina developing later), came together. Their union allowed females to conceive and bear fully formed eggs, which, after hatching, produced male or female offspring according to their nature.
Through this process of sexual mating, certain species from among both the anciens capables and incapables transitioned completely into absolute viviparity. Once nipples developed and became active exclusively in females, they nourished their young by lactation, a method that ensured faster growth and eased the young ones’ struggle for survival compared to purely oviparous species. By this stage, these newly bred beings, especially females, possessed prominent breasts and a much more elaborate womb, restoring to them all the tendencies of viviparous creatures. These viviparous beings, as mentioned before, now began to give birth to live young and suckle them immediately after birth.
Thus, from this grand, unceasing evolution arose reptiles, aerial creatures, amphibians, quadrupeds, bipeds, and countless others, each carrying its own distinct sexual breeding system. Among these stood the primal humans, upon whom I now focus, particularly to address the question of why women generally tend to be shorter than men.
Let us consider this from another angle. Instead of starting from the summit of human evolution, let us descend to its roots and examine the journey from our earliest predecessors to modern humans. Such a perspective may reveal an answer to the height disparity, one perhaps applicable to all species that share similar reproductive organs.
In the earliest human stages, when societies had not yet taken shape, men and women lived much like other creatures of the Earth. Women typically reached menarche between 11 and 13 years in hot regions and 13 to 15 years in colder territories, marking their entry into reproductive maturity. They then mated with mature males, conceived, bore children, and nursed them. Under such a pattern, a woman might have passed through several pregnancies, perhaps four before reaching her twenties, each lasting nine months. Frequent pregnancies and prolonged lactation may indeed have influenced their physical development, limiting their height and growth during those crucial years.
Let us consider growth more closely. Human beings generally live around 80 years. Both men and women reach their maximum physical height by their early twenties, roughly one-fourth of their lifespan. In reproduction, men contribute only a small amount of seminal fluid, around 3 to 4 millilitres, containing sperm. This minor contribution has little effect on their physical development. Women, in contrast, bear the full burden of nurturing the fetus, providing nutrients for its growth. A newborn averages 20 inches in length and 3.2 to 3.4 kilograms in weight. If a woman bears four children before her twenties, the combined birth weight amounts to approximately 13.2 kilograms, all drawn from her body’s resources. Lactation, a defining trait of viviparity, places further nutritional demands on her, relying on blood to produce milk. This burden, unique to women, may have contributed to the height difference observed between the sexes. Nature appears to have favored men in this regard, granting them a certain advantage in the silent contest between the sexes.
Thus, nature has shaped females with a refined anatomy, slightly smaller in stature, and with gentler muscles. A simple analysis might lead one to conclude that if women did not undergo pregnancy before their twenties, they might well match the height of men. I believe this may indeed be possible. Yet height does not always follow direct logic; its path stretches across generations. It may take many centuries for women to reach the same average height as men, provided they postpone childbearing until after their early twenties. Though exceptions will always remain, this hypothesis may perhaps echo across all viviparous and even oviparous species.