1932 –Reports of jackalopes—rabbits with horns—pique the interest of Richard Shope, acancer researcher at the Rockefeller Institute. Working with Rous, he grinds upthe tumors and injects the extract into other rabbits, which then develop the samedeformity. This reveals that the “horns” are actually tumors caused by a contagiouspapillomavirus.

1930s – Thediscovery of two cancer-causing viruses spurs the search for more. Over thenext few years several viruses, including herpesvirus, are found to beresponsible for cancers in frogs, chickens, and mice.

1950s –After the formation of Israel,scientists again wonder about the rarity of cervical cancer among Jewish women.Many epidemiologists think that male circumcision reduces the risk of cervicalcancer by preventing a woman’s contact with smegma—goop that can accumulateunder the foreskin.

1965 –The Epstein-Barr virus, which causes mononucleosis, is found in the cancerouslymph node cells of children with Burkitt’s lymphoma, making it the first knownhuman cancer virus.

1967 – KamalAbou-Daoud notices that Muslim women with circumcised husbands have higherrates of cervical cancer than Jewish women. Other studies in the U.S.S.R. showthat Jewish women with uncircumcised husbands rarely get cervical cancer. Thesestudies begin to erode the circumcision theory.

1970s – Aclose look at cervical cancer cells shows that women with cervical cancer oftenhave traces of genital herpes as well. Some researchers conclude that herpes isthe cause of cervical cancer, even though many women with herpes never developcancer and only about half of cervical cancer patients have a herpes infection.

1975 –Harald zur Hausen begins looking beyond herpes for a viral cause of cervicalcancer, focusing on HPV because of the rabbit studies from the 1930s.Eventually, he isolates two strains of HPV that are found inabout 70 percent of cervical cancer biopsies.

1980s – Researchersat the University of Rochester try toexperiment on HPV but are stymied by a dearth of the virus itself.

1986 –John Kreider finds a way to mass-produce HPV: He collects foreskins from infantcircumcisions, infects them with HPV, and grafts them onto mice whose compromisedimmune systems cannot reject the graft or fight the virus.

1990 –Evidence that HPV causes of cervical cancer mounts, and the race to developan HPV vaccine is on.

1990 –Researchers at the University of Rochester combine antibodies from infected rabbits with the live virus; theproof-of-concept vaccine successfully prevents foreskin-grafted mice fromcontracting HPV on their borrowed private parts.

1990-92 – Robert Roseand other Rochester researchersbuild a protein coat that mimics the shape of an HPV envelope without any viralDNA inside. Built by a harmless baculovirus that grows only on insect cells,the viruslike particles prevent future HPV infection but don’t carry any riskof disease.

1994 – Trialsusing killed strains of rabbit papillomavirus are close to 100 percenteffective in preventing future infections in rabbits. Unfortunately, there’s arisk that some viral DNA could still cause disease, so researchers turn to the viruslike particles for a safer vaccine.

1998 – AlanStorey finds a genetic mutation that increases the risk of cervical cancer and israre among Jewish women. So there was something significant about Jewishimmunity after all—it just wasn’t smegma.

2002 –Studies show that circumcised men have 60% less chance of contracting HPV,which translates into a slight reduction in cervical-cancer risk for theirpartners. This may explain why some circumcision studies from the '50s showed asmall reduction in cervical cancer among circumcised non-Jewish populations.

2005 –Merck and GlaxoSmithKline agree with the National Cancer Institute, Georgetown University,the University of Rochester, and the University of Queenslandto cooperate on two different HPV vaccines.

2005-2006 –Merck and GSK report that the two HPV vaccines made from viruslike particlesare 100 percent effective against the targeted HPV strains.

2006 – Merck’sHPV vaccine, Gardasil, is approved for use in the U.S., and physicians recommendvaccinating all young girls before they become sexually active. A second HPVvaccine, Cervarix, which is made by GSK and targets some different HPV strains, isstill in review by the FDA.