men need to have a pelvic examination and geta prescription for the proper diaphragm. Thecervical cap, less than half the size but used in thesame way, has been available worldwide fordecades. It was not popular in the United States,however, and in 1977 it failed to gain approval bythe Food and Drug Administration (FDA); in1988, the FDA again permitted its sale. Thecontraceptive sponge, which keeps its spermidicalpotency for 48 hours after being inserted in thevagina, was approved in 1983. Like thediaphragm and cervical cap, the sponge has anestimated effectiveness rate of about 85%. Thedevices only rarely produce side effects such asirritation and allergic reactions and, very rarely,infections. The condom, a rubber sheath, is rolledonto the erect penis so that sperm, whenejaculated, is trapped but care must be taken sothat the condom does not break or slip off. Afresh condom should be used for each sexual act.Condoms also help protect against the spread ofVENEREAL DISEASES, and, unlike otherbarrier devices, condoms made of latex doprovide some protection--but notfoolproof--protection against AIDS (see AIDS).Another method of preventing the sperm fromreaching the egg is withdrawal by the man beforeejaculation. This is the oldest technique ofcontraception and, because of the uncertainty ofcontrolling the ejaculation, is considered one of theleast effective. Altering Body Functions Even inancient times, attempts were made to find amedicine that would prevent a woman's body fromproducing a baby. Only within the last century,however, have methods been developed thatsuccessfully interrupt the complex reproductivesystem of a woman's body. The first attempt,made in the 19th century, was based on a legendthat camel drivers about to go on long journeys inthe desert put pebbles in the wombs of femalecamels to keep them from becoming pregnant.Researchers tried to find something that wouldwork similarly in a woman's cervix. The earliestsuch objects...
