**2. How unique is an individual?**

Each human individual is unique to an extreme. Each zygote is the result of a certain probability. At around the fifth month of development, the ovaries of the fetus

contain around 12 million oogonia [6]. A single man's ejaculation contains around 422 million spermatozoa [35], only one of which may fertilize an ovum.

The probability of a certain spermatozoon fertilizing a certain oocyte follows the rule of statistically independent events. For example, if a coin and a dice are tossed at the same time, the probability of getting a head with the coin and a six with the dice are quite independent of each other. The probability of a head and a six at the same time = p (H) x p [6], that is:

 P (H) x P (6) = 1/2 x 1/6 = 1/12. Listing an array of possible results can check this: H1, H2, H3, H4, H5, H6. T1, T2, T3, T4, T5, T6. P (H + 6) = 1/12.

This is known as the multiplication law of probability.

To extend this to the probability of a given spermatozoon fertilizing a given oocyte and resulting in the birth of a baby to a certain couple is as follows:

$$\begin{aligned} \text{P (embryo)} &= \text{P (occyte)} \ge \text{P (spermatozoon)}. \\ &= \frac{1}{12 \ge 10^6} \ge \frac{1}{422 \ge 10^6 \ge 1.93 \ge 52 \ge 62} \\ &= \frac{1}{3.17 \ge 10^{20}} \\ &= 3.17 \ge 10^{-20} \end{aligned}$$

where 12 x 106: average number of oogonia [6], 422 x 106: average number of spermatozoa per ejaculate [35], 1.93: average frequency of sexual intercourse per week [36], 52: number of weeks per year, 62: mean male reproductive life span = average life span [37]—the average age of adolescence [38].

On one hand, the figure of (3.17 x 10–20) is only each individual's chance of being the descendant of a given couple in our present time. On the other hand, each individual could have been born in a different period that may date back to a time that might be easily defined. The true figure for this notation should cover all possible combinations since human life started and between all men and women that have ever existed.

To evaluate this, it is necessary to estimate the total number of people who ever lived. The magnitude of present-day population is impressive. Yet, the inhabitants of the world today are only a certain percentage of the populations of earlier periods. It is necessary, therefore, to include the evolutionary and growth rate factors in the notation.

As to the evolutionary factor, in the past four decades, the phylogeny of the *Hominidae* has increasingly become the focus of investigation. On the Geologic Time Scale, early and modern humans existed in the late Pliocene Epoch of the Tertiary Period and in the Pleistocene and Recent Epoch of the Quaternary Period of Cenozoic Era (Age of Mammals).

Although the fossil record of the last 200,000 years presents an unmistakable well-defined picture of the evolution of our modern species, *Homo sapiens*, the final stages leading to contemporary humans present several unresolved problems. The grade of sapiens contains at least two contrastingly different anatomical types; the bulkily built and heavily muscled Neanderthals and the slim-bodied Cro-Magnons.

#### *The Quantum Theory of Reproduction – How Unique is an Individual? DOI: http://dx.doi.org/10.5772/intechopen.105769*

Moreover, the traditional steps from the *Homo erectus* level of humans to the *H. sapiens* grade have yet to be disentangled [39].

The first undeniable hominid—*Australopithecus*—existed about 4 million years ago. The australopithecines shaded imperceptibly into *Homo habilis*, who integrated slowly into *Homo erectus*, with the latter ultimately transforming into modern *H. sapiens*. However, spirited debate exists over which of the australopithecines occupy a prominent place in the direct ancestry of humans.

It has been suggested that vegetarian *Australopithecus robustus* perished without leaving any descendants and that *Australopithecus africanus* was the forebear of a more advanced hominid. The discovery in 1972 of the "1470" skull and in 1975 of the fossil jaws and teeth that have been classified as the remains of *Homo habilis* and dating back between 1.8 and 3.8 million years, supposing that an older australopithecine gave rise to *Homo habilis*.

The candidate for such an ancestor appears to be the fossil hominid uncovered in 1973 that has been called "Lucy," delineated as the new species *Australopithecus aferensis*. At present, it is safe to state that the *A. aferensis* remains, dating between 3 and 4 million years ago, constitute the earliest definitive members of the family hominidae [39].

The first undeniable hominid—*Australopithecus*—existed about 4 million years ago. The Australopithecus shaded imperceptibly into *Homo habilis,* who intern graded slowly into *Homo erectus,* with the latter ultimately transforming into modern *H. sapiens.* However, a spirited debate exists over which of the Australopithecines occupy a prominent place in the ancestry of humans.

It has been suggested that the vegetarian *Australopithecus robustus* perished without leaving any descendants and that *Australopithecus africanus* was the forbear of a more advanced hominid. The discovery in 1972 of the "1470" skull and 1975 of the fossil jaws and teeth that were between 1.8 and 3.8 million years, supposing that the older australopithecine gave rise to *Homo habilis*.

The candidate for such an ancestor appears to be the fossil hominid uncovered in 1973 that has been called "Lucy", delineated as the new species *Australopithecus aferensis.* At present, it is safe to state that the *A. aferensis*, dating between 3 and 4 million years ago, constitute the earliest definitive members of the family hominidae [39].

As to the growth factor, the human population has undergone three phases of exponential growth. In the first phase of human history, from our species' origin to about 10,000 years ago, the population grew slowly as people existed as hunter gatherers. Cultivation of plants and animal husbandry may have allowed our agricultural revolution and the second phase of exponential growth, from about 8000 B.C. to about 1750 A.D.

The industrial revolution, which occurred about 1850 A.D., promoted the third phase of exponential growth that continues today [40]. Generally, the human population growth since prehistoric times displays a classic J-shaped exponential curve. This curve suggests that the total number of people alive today is approximately equal to the total number who have ever lived and died before us. As the present global population totals 6.3 people, the total number of people who ever lived is over 12.6 billion [41].

To extend this to the probability of a given spermatozoon fertilizing a given oocyte and resulting in the birth of any baby that has ever lived is as follows:

$$=\frac{1}{3.17 \times 10^{20}} \times \frac{1}{6.3 \times 10^{9}}$$

where 6.3 x 109 : total number of males/females who ever lived [41].

$$\begin{aligned} &= \frac{1}{5.04 \times 10^{30}} \\ &= 5.04 \times 10^{-30} \\ \text{Approximately } &= 5 \times 10^{-30} \end{aligned}$$
 
$$\text{Or } \mathbf{1} \text{ in } 200,000,000,000,000,000,000,000,000,000}$$

A two nonillion, octillion, septillion, sextillion, quintillion, quadrillion, trillion, billion, million, and thousand is an indefinitely large statistic! Mathematics used this way is irreplaceable in the pursuit of meaning in which fascination lies. But meaning does not reside in the mathematical symbols. It resides in the cloud of thought enveloping these symbols. The most important dictum in quantum mechanics is that what you can measure is what you can know [42]. To perceive the aforementioned question as inherently meaningless is what quantum mechanics teaches us.
