Population Control
Population explosion can be checked by two methods-population education and birth control.
Population Education 
The knowledge about the relationship between population size and the availability of resources for the welfare of the society is called population education.
1. The students should be convinced about the relationship of overpopulation and unemployment.
2. The citizens should be told how the large size of population is eating away the resources of the state and the reasons for limited availability of health care, education facilities, and other welfare schemes.
3. People should be made aware how large number of children eat away the meager resources of the family with nothing left for bad days, how large families rely on indebtedness to meet emergencies.How child bread earners do not improve the conditions of the family, how uneducated children remain burden on the society, etc. They should be convinced that a small family can live comfortably even with meager resources.
4. Mass Media of Communication.  Radio, television, newspapers, magazines, hoardings and posters should be employed to spread the message of family planning and birth control and its advantages.
The future of mankind depends on stabilisation of human population at a level that ensures basic necessities of life, employment, and happiness.
5. Law about marriageable age should be widely published and strictly enforced 921 years for boys and 18 years for girls).In developed countries, women marry at the age of 25-35 years.
6. As far as possible, stress should be laid on raising the social status of the women.Women having higher social status prefer smaller families. Such women generally marry late,
7. Remove the superstitions and wrong beliefs in the society about higher number of children being God's gift connected with the earthly or heavenly prosperity. 

"Family Planning"
The main objective of family planning or family welfare programme is to prevent the fertilization of the ovum by the male sperm and stop the increase in population growth by various methods, such as contraceptives, intra -uterine device, vasectomy and tubectomy.The contraceptives (nirodh) for males and intra-uterine device, loop for females are used to avoid the pregnancy.Vasectomy is the method of sterilizing male by surgical operation of sperm duct or vasdeferens.Tubectomy is the method of sterilizing female by the surgical operation of fallopian tubes.Whatever the method employed, it must take care of the health of the persons concerned.
Because of the family planning methods, the birth rate in India is reduced to some extent.Government gives incentives to those who adopt family planning.
Ways of Family Planning
1. Late marriage for young persons.
2. Increase in the sources of recreation so as to divert the attention from sex.
3. The couple should not mate between 8-18th day from the start of menstrual cycle.
4. Use of contraceptives.
5. Sterilization.
6. Use of drugs.
7. Abortion.
8. Restrict the family to two children.

Population growth.  Population growth is determined by number of individuals added to the population by births (natality)  and immigration (entry of individuals of the same species into an area from outside). It increases the population size.The number of individuals lost from the population by deaths (mortality)  and emigration (departure of individuals of same species from an area to outside). It decreases the size of local population but the species spreads to new areas.
If more individuals are added than lost, then the population will show positive growth.But if more individuals are lost than added, then the population shows negative growth. But if the two rates are equal, then the population will become stationary and is called zero growth.
Population growth = (Births + immigration) - (Deaths + emigration).
Migration involves the two-way movement of a whole population from one area to another area. Migration is not considered as a factor determining the population size.
Growth Rate.   It is the increase in the number of individuals per unit time per unit number of individuals due to natality being higher than mortality.In other words, growth rate is the difference in the birth rate and death rate in a population. The growth rate of human population is 2%; 0.8% in developed countries and 2.5% in developing countries. It is 1.7% in India as per census of 2001.

Differences between natality rate and mortality rate

(i) Birth or Natality rate. It is generally expressed as number of births per 1,000 individuals of a population per year.  It increases the population size (total number of individuals of a population) and population density.
National average birth rate in India is about 28.6 per 1,000 per year. Among Indian states, Kerala has lowest birth rate of 18 per 1,000 while U.P has highest of 34.8 per 1,000.
Nationalor Birth Rate
\(=\frac { Total\quad Number\quad of\quad Live\quad Births\quad in\quad a\quad year }{ Total\quad Population\quad in\quad the\quad Middle\quad of\quad the\quad year } \times 1000\)
(ii) Death or Mortality rate.  It is opposite of natality rate. It is commonly expressed as the number of deaths per 1,000 individuals of a population per year.
Mortality (Death) Rate \(=\frac { No.of\quad Deaths\quad in\quad year }{ Total\quad Population\quad in\quad the\quad Middle\quad of\quad the\quad year } \times 1000\)
(iii) Fertility Rate.  It is the number of live births per unit time per unit number of fertile females.
Fertility Rate \(=\frac { Total\quad Number\quad of\quad Live\quad Births\quad in\quad a\quad year }{ Total\quad Number\quad of\quad Fertile\quad Women\quad (15-45\quad years) } \times 1000\)

Population density.  Population density of a species is the number of individuals of a species per unit area or volume e.g., number of animals per square kilometer; number of trees per acre of a forest etc. For instance, number of people per square kilometer in 1991.If the total number of individuals is represented by letter N and the number of units of space by letter S, the population density D can be obtained as D = N/S.
Consequences of Higher Population density
As the population density increases in a country beyond its means; it brings following problems:
1. per capita income comes down
2. natural resources like land, minerals, wood, fuel, etc. decrease
3. general health goes down
4. The large population of a country is the result of having large families and the quality of life gets deteriorated accordingly.

Census is the counting of population, age, and sex of individuals, marital status, number of children per couple, number of dependents, number of earning hands, education, literacy, mother-tongue, religion, race, occupation, type of employment, mortality, etc. In India, census is undertaken every ten years, e.g., 1971, 1981, 1991. It takes over one year for the completion of census.Census of our country was carried out in February 2001.

STDs are infectious, communicable and acquired diseases.These pose a major threat to a healthy society as these may lead to a number of complications like pelvic inflammatory disease (PIDs) abortions, stillbirth, ectopic pregnancies, infertility, or even cancer of productive tract.

Preventive measures:  Avoid prostitution and homosexuality, and use condoms.

Counseling and creating awareness among people about the following aspects would help in building up a reproductively healthy society
(i) Reproductive organs
(ii) Adolescence and associated changes
(iii) Safe and hygienic sexual practices and
(iv) Sexually transmitted diseases
Educating people, especially fertile couples and those in marriageable age group about the following would help to raise a socially responsible society.
(i) Available birth control methods
(ii) Care of pregnant mothers
(iii) Importance of breast feeding and
(iv) Equal opportunities for a girl child.

(i) Test tube baby programme - In this method, the ovum of the woman and the sperm of her husband or a donor, are made to fuse ,under laboratory conditions; it is called in vitro fertilisation (IVF). - The zygote or early embryo is implanted in the fallopian tube or uterus respectively for further development.
(ii) Intra Cytoplasmic Sperm Injection (ICSI) - In this method, the sperm is injected directly into the ovum to form the zygote and then embryo transfer is carried out.
(iii) Gamete Intra Fallopian Transfer (GIFn - This method involves the transfer of an ovum collected from a donor female into another female for fertilisation and further development of foetus.
(iv) Artificial insemination - In this method, the semen collected from the husband or a healthy XII donor, is artificially introduced into the vagina or into the uterus (intra uterine insemination). - It is carried out when infertility is due to the inability of the male partner to inseminate the female or due to very low sperm count in the semen.