Humans have believed that gods, demons and instinct drove them to mate and, so believing, they tended to act as expected. The results have been disastrous throughout human history.
Mass starvation in countless times and places has been the all too obvious result of producing more people than there was food available to feed them. Many human groups have waged savage slaughters to gain territory for their rapidly increasing numbers. Huge populations, overusing natural resources, have leveled great forests, promoted erosion and, by so doing, caused floods, famines and other disasters. The natural and artificial wastes of over 6,000,000,000 people--dumped on the earth as well as into its air and water--have exceeded the planet's ability to process poisonous or even great masses of natural solids, liquids and gasses so that disease multiplies on the earth.
The solution remains the same: reduce population. The means to that end has not changed: stop reproducing so wantonly. The usual methods of a achieving that goal--condoms, the pill, the sponge, abortion and other artificial techniques--have failed miserably. The method which remains is to change basic sexual behavior and that will have to begin by changing beliefs.
Human survival, individual and species, depends on the proper use of several bodily processes. Each has a basic function critical to survival and history is full of evidence clearly pointing to the negative consequences of using those processes for other than their basic function.
Consider the respiratory system. It has evolved to intake oxygen and to output waste gasses. Humans who use their respiratory systems to inhale tobacco smoke often die of lung diseases. Those who smoke marijuana form nodules in their neural synapses, thereby reducing their ability to survive. Snorting cocaine causes physical defects and a dependency that leads to self-destructive behavior patterns and greatly inflates the crime rate.
The digestive system, likewise, is intended to convert foods into chemicals usable by the cells of the body. When it is too often filled with alcoholic beverages, the destructive results are well-known and only too common.
The circulatory system of the body evolved to pick up oxygen from the lungs and nutrients from the digestive system for transport to the cells. Again, the devastating outcome of injected heroin into the blood need not be recounted.
The reproductive system of the human body has an equally obvious basic function: procreation. It, too, has a very apparent entertainment value and, as in all the other examples cited, using it for recreational purposes brings down on humankind all of the negative consequences mentioned in this study. It has always been so throughout human history and it remains so in the present.
Nonetheless, to think of having sex only to reproduce and to limit the number of children born in that fashion is an impossible ideal for the vast majority of humans. It is an idea as welcome as teetotalers in a saloon full of barflies but, interestingly, research seems to indicate that people who do not believe that they are driven by instinct to mate and who understand their sexuality and who are not addicted can cope, rather comfortably, with the "impossible ideal".
Constructive change will begin with a belief, that humans are not driven to mate like jungle animals in heat, and it will culminate in a new world view which might be illustrated by the biological fact that female breasts are not sex objects; they are modified sweat glands that produce milk out of the components of blood and sweat. In reality, historical and current human sexual behavior, which seemed or seems normal and natural to those involved, is obsessive-compulsive behavior which need not exist if, finally, the human mind raises itself above the "instincts" that dominated the twisted imagination of Sigmund Freud.