There is a rise in reported cases of gonorrhea and syphilis in the U.S. in 2012, and these increases pertained mainly to men.

In the report, titled Sexually Transmitted Disease Surveillance 2012, co-author Dr. Eloisa Llata of the U.S. Centers for Disease Control and Prevention's (CDC) STD prevention division in Atlanta said that the increases appear to be driven by male homosexuals, or men who have sex with other men.

For gonorrhea, there were 334,826 cases reported in 2012, which is a 4 percent increase from the previous year's 321,849. Rates in 2012 were slightly higher among women than men -- 108.7 versus 105.8 cases per 100,000 population -- but the rate among women increased only 0.6 percent, compared with 8.3 percent among men.

The report states that treatment options for gonorrhea are consistently being limited by growing antibiotic resistance. Currently, the CDC recommends only dual therapy with ceftriaxone and either azithromycin or doxycycline.

For syphilis, the agency found that 15,667 cases of primary and secondary disease were reported in 2012. Compared with the figures from 2011, there were 1,697 more in 2012. That 11.1 percent rate increase was solely among men, while the rate among women did not rise. Cases of syphilis among men who have sex with men rose 15 percent between 2011 and 2012, compared with a 4 percent increase among men who have sex with women only.

For chlamydia, there were 1.44 million reported cases. This was a 0.7 percent increase from the 1.41 million in 2011. The report said that this is the smallest annual increase since nationwide reporting for chlamydia began. The rate of chlamydia in women did not increase - also for the first time since nationwide reporting of chlamydia began - but the rate in men rose 3.2 percent. The overall rate among women was 643.3 cases per 100,000 females - more than twice the 262.6 cases per 100,000 among men. That's because more women than men are screened for the infection, the report noted.

In an interview, Gail Bolan, the director of the CDC's STD prevention division, said, "We know that having access to high-quality health care is important to controlling and reducing STDs. Some of our more-vulnerable populations don't have access. There are a number of men who come in to our clinic for confidential services because they're too embarrassed to see their primary care doctors."

The report also revealed that people of age between 15 to 24 account for more than half of the annual cases of gonorrhea and chlamydia. Undiagnosed STDs, the report stated, cause an estimated 24,000 women to become infertile yearly, because many of these diseases don't show symptoms.

Sexually active women who are 25 years old or younger, and older women with new or multiple sex partners, are recommended by the CDC to undergo annual chlamydia screening and gonorrhea screening. All sexually active men who have sex with men should be screened at least once a year for syphilis, chlamydia, gonorrhea, and HIV.