Science in Christian Perspective



Sociobiology and Population Problems: Perspectives*
Laboratory of Endocrinology and Population Ecology
Biology Department College of William and Mary Williamsburg, Virginia 23185


From: JASA 26 (March 1974): 6-13.
*Supported by Public Health Research Grants MH-08289, HD-04787, and Research Career Development Award HD-07391

A Time of Crisis

We are living in a time of population crisis. The human population is growing too rapidly for the well being of mankind. The pressures of population increase are basic to the problems of pollution and deterioration of the natural environment and in my opinion any program to correct the latter while ignoring the former is doomed to failure. The present growth of the world's human population is 2% per annum. This may not seem like much, but it is clearly alarming when one considers that such a growth rate from the time of Christ would have resulted in a current population of over 20 million individuals in place of each person now living and 100 individuals for each square foot of earth's surface.1

Every species of animal has an inherent maximum ability to increase in numbers referred to as its biotic potential. Increase at a rate equal to or even less than the biotic potential can reach fantastic proportions. For example, it has been calculated that bacteria reproducing every 20 minutes, with 100% survival, would in 36 hours produce a layer one foot deep over the entire earth. Within the next hour of such continued growth, we would be literally "over our heads" in bacteria. Given a few thousand years, any species of plant or animal growing exponentially, or at the compound interest rate, would weigh as much as the visible universe and he expanding outward at the speed of light2,3

When one realizes the tremendous power of population increase and the fearsome consequences of continued unchecked growth, the need for basic information on the dynamics of populations becomes evident. The desire to understand what makes populations "tick" motivated the research of many workers in the field of Animal Ecology long before the popular realization of this population "information gap". Interest centered on the Norway Lemming, the Varying Hare, the Arctic Fox, the Snowy Owl, and voles of various species because of the great fluctuations known to occur in their population numbers. The Norway Lemming, for example, is not only firmly established in the folklore of the region, but has also gained worldwide notoriety because every 3 to 4 years its populations increase to tremendous numbers following which they may move over the countryside like a tidal wave in a mass emigration consuming the crops in their path and being followed and preyed upon by hawks, cats, dogs and other predators. The survivors of these marches upon reaching the sea, plunge into the water and swim until they become exhausted and drown. Charles Elton4 in his book "Voles, Mice and Lemmings" presents documentary evidence that its November, 1868, a steamer traveling up the Trondheim Fjord, took fifteen minutes to pass through a shoal of swimming lemmings.

Evidence of the concern these wildly growing populations brought to the human inhabitants of the area is shown by the following prayer the clergy pronounced against them:

I exercise you, pestiverous worms, mice, birds, or locusts, or other animals, by God the father, that you depart immediately from these fields or vineyards, or waters and dwell in them no longer, but go away to those places in which you can harm no person; and on the part of Almighty Cod, cursing you withersoever you shall go, daily wasting away and decreasing, till no remains of you are found in any place; which may he vouchsafe to do, who shall come to judge the living and the dead, and the world by fire. Amen.4

The notorious fluctuators mentioned above draw attention to themselves and as such misrepresent the facts with respect to population phenomena. Generally speaking, species of animals do not increase to abundances which are excessive for their habitats, and consequently reflect controlling influences. The populations of most species are regulated prior to levels which would be suicidal for them and at which mass starvation or mass mortality from other causes may occur. The mechanisms of regulation vary but three basic forces have been shown to influence population size. These forces are (1) natality (births) the force for increase, (2) mortality (deaths) the force for decrease and (3) movements (immigration-in, or emigration-out). While it is clearly evident that these three major forces influence populations, factors governing their actions are not so evident. For example, predation, disease, and starvation obviously result in removal of individuals from populations. Data are accumulating, however, implicating influences developed intrinsically in each population which may change the vulnerability of individuals to mortality factors or may act to control growth via other means.

Experimental Studies of Population Dynamics

For the past several years, we have been studying the characteristics of growth and control in laboratory populations of Prairie Deermice (Peroinyscus mauiculatus bairdii). This is a small brown mouse, many species of which occur across North America. The data

In research on mice, control of growth in all populations was achieved either by cessation of reproduction or by failure of the young to survive.

available from natural population studies of this mouse indicate that outbreaks rarely occur and that populations are regulated within a rather narrow range of variability. Deermice thus appear to be sensitive to factors regulating population growth and, as such, seem an appropriate species for studies of population regulation.

After selection of the species, we approached the problem first by attempting to record the characteristics of deermouse population growth per se in the laboratory. We placed four pairs of mice in each of several circular pens, enclosing 20 square feet of floor space, covered with a layer of wood shavings. Eight nest boxes were arranged in a circular pattern in each pen and food and water were available in excess at all times (Figure 1). Alternating 12 hours periods of bright and dim light were programmed for each enclosure. Each population was inspected at regular intervals and birth, pregnancies, and the spatial distribution of individuals were recorded.

Under the conditions mentioned above, one might expect an "explosion" of population growth, particularly since pairs of deermice housed in individual cages can produce a litter of from five to eight young every 25 days and protection from predation, disease and environmental fluctuation was provided. Such uncontrolled population growth did not occur, however. Rather, while it took each population a variable period of time to control its growth, such control was clearly

and distinctly achieved.

Not only was growth control distinct, but once achieved, it was of long duration. We do not know how long such a complete shut down of population growth would continue since we have not routinely maintained any populations more than 300 days following cessation of growth. However, our present information indicates that it is extremely rare for young to be born or to survive in a population during this time period.

Another very interesting finding from these studies is that although the populations were maintained under identical conditions, the number of animals present in each when growth was curtailed varied widely. Some populations stopped growing at less than 10 animals while others grew to more than 60! Clearly, those factors determining population control were not influenced directly by numbers per se.

In spite of the wide variations in numerical levels when population growth was controlled, certain measurements revealed similarities between populations.

Control of growth in all populations was achieved by either cessation of reproduction (most frequent) or by failure of the young to survive. Mortality of young was typically due to either abandonment by their mothers or to excess "care". Reproductive females frequently interfered with each other in the care of young and occasionally, two or more females would attempt to retrieve or carry young in their mouths to different nest boxes. This resulted in continual moving of young and during the process more than one female might grasp the same young and attempt to carry it to different nest boxes! Such handling eventually resulted in the death of the young following which they were usually consumed.

The reproductive attributes of the animals were also similar between populations. For instance, an average of only two females produced young even though each population averaged 6 or more times that many. Even more interesting, only 5-15% of the females born into the populations and living longer than 100 days produced young. This phenomenon is particularly intriguing since mice maintained as mated pairs in single cages may have young prior to 60 days of age. Thus, something about living in a population which is controlling its growth inhibited reproductive function in 85-95% of the females and did so irrespective of the number of mice present when each population stopped growing! Such inhibitory influences were also evidenced by the reproductive organs of both males and females. Table 1 gives the average weights of the reproductive organs of mice born into populations and reaching at least 100 days of age compared to mice of similar age reared in pairs from weaning in a cage separated from the populations. None of the females used in this analysis had ever had young. The reproductive organs (ovaries, uteri, testes and vesicular glands) of mice reared in bisexual pairs averaged 3 or four times as large as those of population animals.

What is the reason for these severe inhibitory effects related to reproduction? Why do populations stop growing? Is one response the result of the other or are unknown influences responsible for both? We are not sure of the answers to these questions but we do have some information suggesting at least a partial answer. Our logic is as follows; Growth of our experimental populations was controlled at markedly different numerical levels under identical conditions of the physical environment while food and water were available in surplus. Since similar population, reproductive and other physiological characteristics were exhibited between populations, control of growth must be related to behavioral influences developed intrinsically in each population.

At the present time we have no clear information as to what these behavioral factors are which stimulate population regulation. Social behavior would seem to he of importance. A logical assumption might be that aggressive behavior might be directly involved. However, our data indicate that very little overt aggressive behavior takes place in the populations and that which does occur is expressed toward only a few individuals. Other behaviors have been noted, however. Two are most obvious and, perhaps, indicative of changes in the populations related to growth. These are the development of food hoarding behavior and the crowding together of large numbers of animals.

Food hoarding is the removal of food pellets by the mice from the central hopper where they are normally added. These pellets are transferred or "hoarded" to some location within the enclosure. An adult female (usually one of the females used in founding the population) typically initiates hoarding behavior although a few other mice may eventually participate. The hoard is not defended and other members of the population are permitted to eat the food as long as they remain at the site of the hoard. If, however, food is removed from the hoard to be eaten elsewhere, the mouse so doing is immediately chased by one of the boarders, the food taken away and returned to the hoard. If, during this process, the chased mouse returns to the hoard with the food, there is no further interference from the boarder-guardian and the food may be consumed at the site of the hoard. Hoarding and maintenance of the hoard appears to be an attempt to structure or organize the physical environment and individuals of the population in accordance with a pattern determined by the boarders.

Table 1
Comparisons of the weights (mg) of the reproductive organs of population and control mice5

Organ                                    Control                   Population            Comparison 
                                            (Mean± SE)              (Mean ± SE)                  P
Ovaries (Paired)                    7.01 t .62                   2.04 ± .25                 <.005 
Uterus                                 25.14 ± 2.49               6.09 ± 1.13                <.001
Testes (Paired)                    202.24 ± 6.45            69.98 ± 20.22             <.001
Vesicular Glands (Paired)    151.89 ± 10.06          27.59 ± 14.87             <.001

SE Standard Error of the Mean, P=Prrobability of Calculated "t" value

In approximately 95% of the populations, such behavior preceded cessation of growth. We are continuing to study this behavior to sec if it is causal or merely symptomatic of those forces bringing about cessation of population growth.

"Huddling" is another of the behaviors observed. As each population grew, the animals began to aggregate in one or two locations within the enclosure. Such behavior began at variable time intervals prior to cessation of growth and in some populations, 95% of the mice combined in one aggregate! Huddling appears to be an attempt on the part of the mice to lose individuality. The animals involved spent most of the time sitting and sleeping and occasionally leave briefly to eat or drink. The "huddlcrs" are frequently walked over by other "active" members of the population who on occasion have been observed to rake shavings over the huddle! At the moment, we do not know what relationship aggregation behavior has to population regulation. It may be a result of altered physiological or hormonal factors or, indeed, may be involved in the production of such alterations.

The above information has been obtained from studies of populations as they grew from a few founding animals to the time at which growth was controlled. With this background of information on population growth available, we have begun an approach utilizing experimental manipulation to understand more clearly the phenomena described. Two of these experiments have produced exciting results which are pertinent to this discussion.

Given the evidence that inhibition of reproductive maturation and function is related to population growth, a logical consideration is whether or not such inhibition is permanent. Our data indicated that if the animals remained within the populations, they would remain reproductively nonfunctional. We, therefore, removed inhibited males and females from their populations and paired them with fertile mates. Other, nonreproductive males and females were paired with similar animals from a different population.

Twenty-five percent of the population animals paired with fertile mates produced young within 30 days and 75% became parents within approximately 90 days following pairing. None of the males and females paired from different populations reproduced within 30 days and it was not until 180 days subsequent to pairing that 75% reproduced.
This experiment indicated that most mice could become reproductive if removed from the population and paired with fertile mates. A period of physiological and behavioral adjustment following removal from the populations appears to he necessary prior to reproduction and this may he likened to a delayed puberty. Further this reproductive reorganization which occurs following pairing apparently is dependent upon some kind of mutual stimulation among the paired animals. This is shown by the fact that none of the pairs in which both the male and female were from populations reproduced within 30 days. Further, the time required for reproduction by 75% of these pairs approximated twice as long as that required by population animals paired with fertile mates. Thus, animals from different populations who were paired with each other lacked the reproductive "mistique" in their relationships as evidenced by population animals paired with fertile mates! The results of this experiment

If the present growth rate continues, in 30 or 40 years, one out of every 10 persons ever born will be living at that time!

demonstrated once again the influence of the population in the prevention of reproduction by animals which were capable of reproducing once removed from the population situation. It is also worth remembering that these inhibitory influences were operative in the presence of surplus food and water.

A second group of very interesting results was obtained from an experiment designed to inquire into the mechanisms of communication which must be occurring in the populations. Communication by olfactory cues seemed a logical mechanism to examine because many animals depend to a great extent on the sense of smell to sample the environment and many release chemical messengers called "pheromones". I decided to test the possibility that pheromones released by animals in our experimental populations might be responsible for the inhibition of reproductive maturation and function observed. In order to do this, we paired 21-day-old male and female mice and kept them until they were 100 days of age on each of the following types of bedding: (a) shavings soiled by populations at asymptote, (h) shavings soiled by reproducing bisexual pairs, and (c) shavings unsoiled by mice. The shavings were changed once per week. Records were kept of the numbers of pairs in each treatment which reproduced and, following sacrifice, the reproductive organs were weighed and compared. The results were startling! Deermiec reared on shavings soiled by populations had a higher reproductive rate and generally larger reproductive organs than those maintained on shavings soiled by isolated bisexual pairs or on clean shavings. For example, 70% of the pairs maintained on population shavings produced young by 100 days of age. Only 30% of the pairs reared on clean shavings reproduced by the same age. These results demonstrated that although females and males in the populations were inhibited reproductively, there were materials on the shavings of these same populations which stimulated such development and function in animals using those shavings as bedding outside of the population. These data further emphasize the inhibiting influence of the population environment even in the presence of such materials since less than 15% of the females and males in the populations reach sexual maturity.

What does all this mean? Does it fit together and if so-how? A summary of the "state" of the science may help to point the way to the answers to some of these questions.

The information obtained thus far from experimental laboratory studies of several species is that populations do not continue to increase indefinitely even though provided with excess food and water. Populations of small mammals as well as of most other forms characteristically grow in a manner described by the logistic curve with growth beginning slowly, rapidly increasing and eventually slowing markedly or completely ceasing (Figure 2). This leveling off of the population growth curve is referred to as the population asymptote. An understanding of the mechanisms 

by which population growth is controlled is far from complete. There are, however, certain additional characteristics of populations at asymptote which are noteworthy in this respect. The first such characteristic is that the numbers of animals present when growth is controlled varies widely between populations even though conditions of the physical environment are maintained as nearly identical as possible. A second characteristic related to the first is that in spite of the marked differences in numerical levels when growth is controlled, the physiological alterations appear to be similar between populations. For example, the weights of the adrenal glands and spleens of animals from asymptotic populations tend to be larger and the eosinophil numbers and weight and activity of reproductive organs are less than for isolated pair controls. These data, therefore, suggest that those factors which control the growth of populations may produce physiological effects directly related to the approach of a population to asymptote and not to the numbers of animals present per se Thus, density is relative to social factors and we must think of the numbers of animals in a population in a qualitative as well as in a quantitative sense. Mechanisms of control thus appear to be related to a kind of "social pressure" developing intrinsically in each population which may he communicated through one or more of the senses of touch, smell, sight, hearing and taste. These stimuli are received in the brain and interpreted in some way by the ventral part of the brain (the hypothalamus). The hypothalamus is involved in controlling the pituitary gland, the master gland of the endocrine system, which influences the development of reproductive capacity. Normal release of hormones concerned with the maturation of the reproductive organs may be prevented. These are merely theoretical ideas as yet. We are continuing to explore the complete system involved including the behavioral patterns triggering the response and the neural and endocrinological mechanisms producing population control.

Human Population Problems

With this background of what is known about experimental laboratory populations, let us now consider briefly the problems of the human population. Assuming that the first "man" appeared between 1,600,000 and 600,000 years ago, the world population is now in the logarithmic phase of a typical growth curve after a long period of slow increase,-similar in many respects to the theoretical curves of growth of experimental populations (Figure 2). This rapid increase in the human population is largely the result of advances in medical knowledge which have centered attention upon decreasing mortality while doing very little to regulate natality3.

To illustrate the rapidity with which the world's population has grown-it took from the beginning of man until 1850 to reach a population of one billion people. By 1930 (80 years later) a population of 2 billion was attained. Thirty years after that (1960) the world's population was 3 billion. By 1975 (15 additional years), four billion people will inhabit this earth. In 1968 we passed the 3.5 billion mark. Some predictions are that shortly after the year 2000 we will have twice as many people on earth as in 1968!

Population growth tends to gain momentum. The time required for the population to double is rapidly decreasing. Once the population reached 1 billion in 1850, doubling to 2 billion took place in 80 years. The next doubling to 4 billion is estimated by 1975, requiring 45 years. At our present rate of growth (2%), doubling is achieved at a 35-37 year rate. From the time of "Adam and Eve" until now, man's population has doubled 31 times. If it doubles 16 more times, there will be 1 square yard for each man, woman, and child on earth7.

The following clarifies our present situation and is even more alarming. If there have been almost 77 billion births since the Stone Age, then almost 1 out of every 22 persons born since then is alive today, and if the present growth rate continues, in 30 or 40 years, one out of every 10 person ever born will be living at that time!8

The present growth rate will not continue indefinitely and must not continue any longer if we are to avoid disaster from many quarters. The three forces, natality, mortality and movement I mentioned previously as influencing the populations of other organisms, likewise influence the human population. If we hurry, however, we may still have time to regulate the action of these forces as they control our population.

Obviously, movement offers no solution to our population problems. We are all confined together on our "Space Ship Earth" and no practical means of escape are available to us.

This leaves only the forces of natality and mortality to determine our population future.
Factors which may produce sufficient mortality to at least temporarily curb the population growth have been suggested as follows:

1. The possibility of release upon us of some lethal agent in time of war which could kill a high proportion of the population.
2. An outbreak of disease capable of decimating the population.
3. The rapid deterioration of our environment and accumulation of toxic products.
4. Exhaustion of the food supply.

I will not discuss the first 3 of these factors producing population control through increased mortality. They are all effective producers of mortality and the probability of their action increases as population growth continues unchecked.

I wish to discuss briefly the mortality factor which has already begun to take its awful toll and will increase its effective action as time goes on. I speak of the problem of starvation. Present estimates are that at least one-half billion people are undernourished (deficient in calories or slowly starving)'. Estimates of the number actually perishing annually from starvation begin at 4 million and go up dependent upon the official definitions of starvation which may conceal the true magnitude of hungers' contribution to the death rate.

Some feel that the battle to feed the world population is now lost and that by 1985 we will have world wide famines in which hundreds of millions of people will starve. Merely to maintain the presently inadequate nutrition levels, the food requirements of Asia, Africa and Latin America will conservatively increase by 26% in the 10 year period measured from 1965 to 197510. World food production must double in the period 1965-2000 to stay even. It must triple if nutrition is to he brought up to minimal levels. It is evident that we must place top priority on development of dietary supplements, development of high yield, high nutrient content food crops, maximum food production in this country and rapid and effective training in the know how of food production in food-stress areas of the world.
Unfortunately, even with increased attention given to increasing food production in the world, many authorities agree that it is doubtful that sufficient changes can be made fast enough to prevent mass starvation. Further, the need for additional food resources will continue to expand unless something is done about natality.

In a report published in 1969 summarizing the findings of the President's Science Advisory Committee on the World Food Supply, the following statement was made:

It was decided that the time period of two decades, namely 1965-1985, would likely he the most critical period of the problem to be experienced. One of two conditions will probably become apparent by the end of this 20 year span in the developing nations with which we are generally concerned. ( 1) Either the population growth will have been brought under control and a balance will have been developed between the population and the food supply, or (2) some nations, possibly many, will have passed the crest and will be accelerating on a declining grade of malnutrition, economic deterioration, and political instability to the point where no reasonable solution to the problem can be found.11

Thus, it is evident that the birth rate must he curbed. This may he achieved voluntarily or involuntarily.

At the present time we have little data suggesting that intrinsic mechanisms of population control may produce sterility in human populations similar to that found in the experimental populations of deermice. In a sense, the 

We must reach the point through legislative means when the financial and social rewards will cause each couple to limit its family.

human population possesses the capability of developing such intrinsic mechanisms of control is only academic because if our experimental data tell us anything with respect to the human population, it is that we must regulate before such mechanisms of control operate. The simple reason is that most of us would not wish to live under the conditions which would exist at that time.

The human population should, therefore, he regulated at some level commensurate with the quality of life desired. While each culture may vary as to what is considered the quality of life, all peoples desire freedom from hunger, disease and the opportunity to work out a rewarding future for each individual and his family.

How can we achieve such a regulation of the human population while maintaining as little interference with the freedom of individuals as possible? Of course, this is the area where the scientist speaks only as any other citizen, but possibly with a greater sense of urgency.

The importance of birth control education with emphasis on the principles of population biology at the high school, college and adult education levels, as well as in the home, cannot be exaggerated. A recent study at Cornell University revealed an alarming lack of personal responsibility for the future population situation and a level of ignorance of the biology of sex unexpected on the part of the "educated"12. Sixtyfive percent of those responding to a questionnaire indicated that they wanted 3 or more children in their families (26% wanted more than 3 children). A re-orientation of social values and attitudes regarding births is urgently needed. We need an individual awareness of the tragedies associated with too many babies and rising social pressure against more than 2 or 3 per family.

We must make available to all, irrespective of marital status, the information and techniques with adequate medical advice to prevent unwanted conception. Recent information supplied by the "Commission of Population Growth and America's Future" indicated that approximately 19% of all births during 1960-65 were unwanted. True, many of these "unwanted" babies became wanted. In my opinion we as Christians and "moral" people do not have the right to withhold birth control information and techniques, which have largely been obtained by public funds, under the assumption that to release such information would encourage immorality or promiscuity. Pregnancy should not be regarded as a punishment. We must think of the postnatal life of the unwanted child-not punishment for the unmarried mother.

Unfortunately, availability of such information and techniques of birth control on a world-wide basis is not enough. Planned parenthood is not population control for the simple reason that too many parents may desire too many children for the good of the population.

We must reach the point through legislative means (tax rewards, etc.) when the financial and social rewards will cause each couple to limit its family.

To young people, I can only apologize that we of my generation have allowed the population and the abuse of our environment to reach such a sorry state. We urgently need your aid in preserving and making available to all those physical and spiritual requisites which make life more than mere existence. We must succeed or we may be witnesses and contributors to man's inhumane treatment of his fellows on a scale never seen before. We must not reach the condition referred to in a recent speech by Dr. James Bonner, California Institute of Technology, when he stated:

We will, I suspect, begin to regard the starving populations of the underdeveloped nations as a race or species apart, people totally different from us as indeed they will he. 'They are just animals' we will say, 'and a serious reservoir of disease.' The inevitable culmination of the two cultures will be that the one culture (the rich) will devour the other.11

What about the U.S. population? The April 1 census has shown our population at 204,765,770. Figures recently published by the Commission of Population Growth, and the American Future show that our population is increasing at the rate of 6,000 per day or over 2,000,000 per year. Our current rate of increase will bring us to 300,000,000 by around the year 2008. While our rate of increase has slowed considerably and has been a cause for optimism in the press and elsewhere, there are at least two additional considerations which cloud such optimism.

The first consideration is that the number of people in the child bearing age is increasing. These are babies from the post war baby boom who have grown up. Even if the average family size drops to a 2 children, and there is no indication that it will, the population will still be increasing by the year 2000.

The second consideration is clearly illustrated in the following taken from the Eli Lilly Company News Letter:

If all the people of the world could he reduced proportionately into a theoretical town of 1,000 people, the picture would look something like this: In this town there would be 60 Americans (6%), with the remainder of the world represented by 940 persons...The 60 Americans would have half the income of the entire town with the ether 940 dividing the other half. (About 350 of these would be practicing Communists, and 370 ethers would he under Communistic domination.) White people would total 303, with 697 being non-white. The 60 Americans would have 15 times as many possessions per person as all the rest of the world. The Americans would produce 60 percent of the town's fend supply although they eat 72 percent above the maximum fend requirements . . . Since most of the 940 non-Americans in the town would be hungry most of the time, it would create ill feelings toward the 60 Americans who would appear to be enormously rich and fed to the point of sheer disbelief by the great majority of the townspeople. The Americans would also have a disproportionate share of the electric power, fuel, steel, and general equipment. Of the 940 non-Americans, 200 would have malaria, cholera, typhus, and malnutrition. None of the 60 Americans would get these diseases or probably ever be worried about them.11

Conservative estimates are that the average child born into the United States will put at least 25 times as much stress on the environment as a child born in India due to our high rate of production, consumpion

We must not utilize clever interpretations of the Scriptures to quiet our concerns and lull us into complacency regarding ecological problems.

and waste disposal. Clearly this proportionate use of the world's resources, many of which are nonrenewable, cannot continue. Serious questions have been raised as to whether it is possible to raise today's world population to a standard of living comparable to ours. Clearly, the longer population control is delayed the more difficult and unlikely the sharing of the "quality" things of life and the more certain that the standard of living which we consider basic may have to be lowered.

The social, political, ethical and religious implications of the problems which face us in the regulation of our population are multiple and complex. Many of these problems do not have clearly discernible answers. For example, what legislation will be most effective in regulating reproduction and yet consistent with the dual principles of freedom of the individual and his responsibility to society? How can the necessity for population regulation be impressed on the so-called developing nations, which have the highest birth rates, but which regard such attempts as interference in their private affairs and suppression by the developed nations?

What are acceptable methods of birth control?

1. Prevention of union of sperm and egg (abstinence, coitus isiferroptos, condoms, diaphragms, anti-ovulation materials, etc.).
2. Prevention of implantation of the fertilized ovum in the uterine wall (IUD's, morning after techioques, etc.).
3. Removal of the implanted fertilized egg (embryo) up to some stage of development (abortion).

These are difficult questions. Urgency requires that we make decisions without satisfactory answers. Make no mistake about it, our population will be controlled either by mortality or a reduction in natality. As Christians and humanitarians, we cannot accept the former means. The choice for a short time is still ours, but we must act! We have the techniques to prevent catastrophe, do we have the foresight?

What can we do as conservative evangelical Christians and members of the American Scientific Affiliation? Certainly, we must face problems squarely and realistically. There is an ecological crisis. We must not utilize clever interpretations of the Scriptures to quiet our concerns and lull us into complacency regarding ecological problems. In the minds of some, "Man is here to keep nature running smoothly". More realistically man is part of nature and the biosphere and unfortunately the data indicate that much of man's interaction with nature has been disruptive.

Granted that many of our environmental problems are basically due to man's being out of harmony with God, solutions to the problems of population and environmental deterioration cannot wait upon the correction of man's basic problem. This involves a conscientious stewardship in which man is regarded as part of God's creation and his ecological as well as social actions of moral concern and responsibility. In light of our Christian commitment, we must become  involved in seeking solution to the problems besetting  us. Perhaps the American Scientific Affiliation is here "for such 'a time as this". 


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