Birth control and contraception refer to the conscious regulation of the conception and birth of children, also known as family planning.

Generally, birth control and the use of contraceptive methods are employed to limit the number of children that are born or to spread out their time of birth.

Sometimes birth control is practiced for a specific period of time (several months or years), and sometimes — when there is a medical or other reason to end conception — it is practiced until the end of fertility. Birth control strategies of various kinds and with varying degrees of effectiveness are used around the world.

Without use of any birth control method, for every 100 fertile women 60-80 will become pregnant during the course of a year in which intercourse occurs regularly.

For girls age 15-19, this figure is about 90 percent. The modern birth control movement began in England, after the writings of Malthus on the potential for population growth sparked concern about world overpopulation.

The first clinic devoted to birth-control in the U.S. was launched by Margaret Sanger in 1916. Sanger, a nurse, organized the first national and international conferences on birth control and organized a committee to lobby for birth control laws.

The Catholic Church has been a major opponent of the birth control movement. While the Catholic Church accepts abstinence from intercourse and use of the so-called rhythm method (limiting intercourse to the least fertile periods in a woman's monthly cycle) as acceptable birth control activities, it strongly and vocally opposes other methods.

For individuals who choose to use birth control, various approaches are available. Considerations in selection include safety (e.g., protection from sexually transmitted diseases and HIV, as well as avoiding side effects of birth control use), effectiveness, convenience, cost, personal acceptance, and partner attitudes.