Abstinence is the only sure shot method of contraception that works. Most contraceptives have, after all proper precautions taken and all unforeseen possibilities discounted, a certain margin of error. The only contraceptive which is to some extent capable of preventing sexually transmitted diseases including AIDS is the Condom.

Sponge method of contraception has been found to be slightly less effective than methods such as using a diaphragm in studies conducted in both the U.K. and the U.S. Sponges are said to fail nearly 25 percent of the time in the U.K. and 17 percent of the time in the US. The failure rate of diaphragm is around 11 and 13 percent respectively. This could prove that sponges which use a combination of a mechanical and chemical process to prevent pregnancy by killing sperms are less effective. One could also argue that Englishmen are more virile or that English women are more technically incompetent then their American counterparts.