Because of contraception, pregnancy need not be viewed by women as punishment for sexual activity but as a planned and desired event. Most of the contraceptive methods used in developing countries at present were introduced during the 1960s, but use of contraception has a long history and some methods date back to antiquity. Contraceptive pills were already used around 2000 BC in the form of mercury and arsenic tablets. Their effectiveness was questionable. The role of hormones in human reproduction began to be understood only in the early 1900s. The discovery of progesterone in a Mexican iguana in the 1940s permitted production of progesterone on a large scale. Estrogens had been identified around 1930. Human trials of a contraceptive pill beginning in 1956 in Puerto Rico demonstrated that progestins could prevent pregnancy by suppressing ovulation. Later on, estrogen was added to reduce menstrual irregularities. The 1st generation of combined oral contraceptives contained very high levels of hormones associated with high rates of side effects. Numerous formulations with lower hormonal contents became available beginning around 1970 and constitute the principal formulations in use today. A number of long acting hormonal methods based on progestins have been developed, including injectables, some IUDs and vaginal rings, and implants. The 1st commercially available injectable, norethisterone enanthate, did not acquire the wide distribution of medroxyprogesterone acetate, sold as Depo Provera and used to treat various pathological conditions as well as for contraception. The 1st true IUDs were small stones placed within the uteri of camels by nomads to prevent pregnancy during long caravans. An IUD was developed in 1909 by Richter, and the 2 most widely used models before 1960 were the Grafenberg and Ota silver rings. Use of the 2 rings became rare for medical reasons after 1935 despite their efficacy. Safe plastic IUDs which appeared beginning in the early 1960s were flexible and capable of returning to their original shape after insertion. The Lippes loop was the 1st highly successful IUD. Bioactive IUDs containing copper were developed in the 1970s. Research is underway to develop IUDs which will resist expulsion, reduce bleeding, be more appropriate for multiparas, and last longer. IUDs are used to treat intrauterine adhesions as well as for contraception. A gummy substance used to block the cervix was described in Egypt in 1850 BC. Japanese and Chinese prostitutes of antiquity placed oiled bamboo paper at the cervical opening for contraception. Diaphragms and cervical caps were developed in the 19th century in Germany. Large scale production became possible after 1880 with the development of better, more durable, and cheaper rubber. An Egyptian writing in 3500 BC began the study of spermicides. Numerous substances such as lemon juice and honey have been placed in the vagina to avoid pregnancy. Such substances are available to all women and some were reasonably effective. Current research is directed toward development of spermicides which will also prevent sexually transmitted diseases. The 1st condoms were made of animal skins by an English physician to prevent transmission of venereal diseases. Rubber condoms appeared in the early 20th century and are widely utilized in some family planning programs. Pregnancy vaccines and a reversible hormonal method for men are among methods under development.