This Week in Sex is a weekly summary of news and research related to sexual behavior, sexuality education, contraception, STIs, and more.

Could Prostate Cancer Be Sexually Transmitted?

There is precedence for the idea that sexually transmitted infections (STIs) can cause cancers: We know that two strains of human papillomavirus (HPV) cause 70 percent of all cervical cancers and that the virus is likely responsible for the recent rise in head, neck, and throat cancers as well. Now researchers are suggesting that an STI may also be responsible for cases of prostate cancer.

Researchers at the University of California infected human prostate cancer cells with the common STI trichomoniasis (known as trich). They found that the parasite that causes trich produced a protein that promotes the growth of both benign and cancerous prostate cells.

There is other research to suggest a connection between prostate cancer and trich; a 2009 Harvard study found that a quarter of men with prostate cancer had trich, and those who did had more advanced tumors.

Even when put together, however, these studies are not enough to confirm that prostate cancer is indeed caused by trich. In fact, Nicola Smith, health information officer at Cancer Research UK, told the BBC that previous evidence in patients failed to show a clear link between prostate cancer and this common STI.

More research is clearly needed, as 233,000 men in the United States are expected to be diagnosed with prostate cancer this year, and there are an estimated seven to eight million cases of trich annually. It is important to remember that unlike HPV, trich can be cured with antibiotics. Moreover, consistent and correct use of condoms can prevent infection in the first place. If confirmed, these results could suggest that some prostate cancers would be preventable.

Which States Have the Most STIs?

We know that while there is an STI epidemic in this country, incidence and prevalence of infections are not evenly distributed throughout the 50 states. Some states and regions have far worse track records than others. The good folks at Nerd Wallet recently culled the data and put it all together in an easy-to-read list of the best and worst states when it comes to STIs.

To calculate the ranking, they looked at the prevalence of chlamydia, gonorrhea, and syphilis. All three of these STIs are reportable to the Centers for Disease Control and Prevention (CDC), which means we have a clear picture of how many cases of each disease have been diagnosed in each state. The states were ranked according to prevalence of each STI, and then the rankings were added together to get the overall score. (In the case of a tie, the final ranking was made based on the state’s chlamydia rate, because that is the most frequently reported STI.) Though this should be obvious—since we are looking at it from the point of view of humans and not pathogens—the “best” states are those with the fewest cases of STIs.

The five best states are: West Virginia (48th for chlamydia, 41st for gonorrhea, 49th for syphilis); Maine (49th for chlamydia, 44th for gonorrhea, 43rd for syphilis); Vermont (46th for chlamydia, 46th for gonorrhea, 44th for syphilis); Utah (47th for chlamydia, 45th for gonorrhea, 42nd for syphilis; Wyoming (37th for chlamydia, 50th for gonorrhea, 46th for syphilis); and Montana (35th for chlamydia, 48th for gonorrhea, 50th for syphilis).

The ten worst states are: North Carolina (tenth for chlamydia, sixth for gonorrhea, 24th for syphilis); New York (11th for chlamydia, 16th for gonorrhea, seventh for syphilis); Texas (13th for chlamydia, 13th for gonorrhea, sixth for syphilis); Illinois (ninth for chlamydia, tenth for gonorrhea, eighth for syphilis); and Arkansas (seventh for chlamydia, seventh for gonorrhea, ninth for syphilis).

This list provides some good information for state lawmakers, who can and should be doing a better job ensuring education about sexual health and providing sexually active people of all ages access to condoms and other contraceptive methods needed to prevent unintended pregnancy and STIs.

Support for Same-Sex Marriage at All-Time High

This week, in the latest of a series of decisions paving the way for same-sex marriage across the country, a judge in Pennsylvania struck down that state’s ban. Republican Gov. Tom Corbett, who is running for re-election, says his administration will not challenge the decision. While that would seem unheard of a few years ago, other Republican governors—including Chris Christie in New Jersey, Susanna Martinez in New Mexico, and Brian Sandoval in Nevada—have also decided to stop fighting same-sex marriage.  A new Gallup poll suggests this is a wise move, as support has reached an all-time high.

Gallup has been asking the same question since 1996: “Do you think that same-sex couples should be or should not be recognized as valid, with the same rights as traditional marriages?” The first time the question was asked, 68 percent said no and only 27 percent said yes. In 1999 the needle moved a tiny bit, with 62 percent saying no and 35 percent saying yes. In 2004, 55 percent said no and 42 percent said yes. Though the number changed incrementally from there, by 2011 there was a cross-over, with more Americans supporting same-sex marriage than opposing it.

The newest poll, conducted in May, shows the mirror image of what was going on just one decade ago: Now, 55 percent of Americans believe that same-sex marriages should be valid, and only 42 percent said they should not be.

Harvey Milk Stamp Released

Last week, on what would have been his 84th birthday, the U.S. Postal Service released a stamp featuring a picture of Harvey Milk, one of the first openly gay elected officials in the country. Milk, an outspoken advocate of gay rights who had been elected as a city supervisor in San Francisco, was assassinated along with the city’s mayor in November of 1978. In a White House ceremony dedicating the stamp to Milk, Postmaster General Ronal Stroman said, “Harvey Milk joins other civil rights pioneers who have been honored with stamps including Martin Luther King Jr. and Caesar Chavez.”

Anne Kronenberg, who served as campaign manager during Milk’s run for office and is the co-founder of the Harvey Milk Foundation, joked at the ceremony, “During our campaign we didn’t have enough money for postage. So Harvey, here you are today on a United States Postage stamp and I say this is a wonderful thing because you will be there forever.”