Progress in science and the improvement of living conditions have led to the rapid growth of world population. Modern medicine, for example, has made it possible for babies to grow up healthily and for people to live longer. With improved living conditions particularly in the countryside, people tend to have larger families. As a result, the world population has increased so rapidly that it has now exceeded 6 billion.
But the overgrowth of population presents a threat to the existence of food supplies and shelter space. However, the limited productivity and scarce world resources can hardly meet the needs of the ever-increasing population. Thus, in the long run, the overgrowth of the world population will only harm mankind.来源：www.exam
To guarantee the steady development of human society, mankind must realize the consequences resulting from a fast population growth and carry out a family planning program. Only by adopting effective meausres, can human society develop steadily and have a bright future.
