Female hormonal contraceptives gave women unprecedented control over their reproductive health with the approval of the pill on June 23, 1960. But a similar male version has never reached the market. Physiological differences between men and women’s reproductive cycle, along with economic and regulatory problems, have stood in the way of a male pill for 50 years, scientists say.The main difference between designing a contraceptive for men, as opposed to one for women, is the number of reproductive cells that the pill would need to stop, said John Amory, associate professor of medicine at the University of Washington Medical Center in Seattle. Whereas a pill for women only needs to prevent the release of a single egg once a month, a pill for men faces a larger, constant challenge.“People have been trying to develop a male analog to the pill ever since the female pill came out. Turns out its much more difficult,” Amory told Life’s Little Mysteries. “The … [Read more...] about Why Isn’t There a Male Birth Control Pill?
A new study suggesting that circumcision can decrease sexual pleasure is drawing the fire of scientists in the field, who say the findings are flawed.The study, published in February in the British Journal of Urology International, found that circumcised men reported less sexual sensitivity than their uncut brethren.But several experts say the study has too many weaknesses to draw any conclusions from it."The study is pretty flawed," said Douglas Diekema, a pediatrics professor at the University of Washington, who was part of the American Academy of Pediatrics 2012 task force on circumcision. "I read the conclusion and then I read the study, and I said, 'Wow, they went overboard in what they're concluding.'"The study used a biased sample population, didn't measure sensitivity changes before and after circumcision, and found only a tiny difference between the two groups, which is clinically meaningless, making it impossible to conclude from the results that circumcision reduces sexual … [Read more...] about Does Circumcision Hurt Sexual Pleasure? Study Draws Fire
Men with low testosterone levels after age 40 have a higher risk of death over a four-year period than those with normal levels of the hormone, a new study suggests.It's not clear, however, if the two are directly related, and researchers say that it's possible a third unknown factor is responsible for both low testosterone levels and increased mortality.The study, led by Molly Shores of the VA Puget Sound Health Care System and the University of Washington, Seattle, is detailed in the current issue of Archives of Internal Medicine.Wild variation Testosterone levels can vary wildly between different men and even within individuals as a result of illness or stress. However, studies have consistently shown that levels of the hormone decrease as men age.Testosterone levels peak during a man's late 20's but decline soon after, decreasing about 1.5 percent per year after age 30. The decline is thought to be due to age-related changes in the testes, where the hormone is produced, and in the … [Read more...] about Men with Low Testosterone More Likely to Die
A heterosexual person infected with HIV will transmit the virus to their partner once in every 900 times the couple has unprotected sex, according to a new study conducted in Africa.However, the exact number of sexual acts that are needed to transmit the virus can vary tremendously depending on the amount of the virus in the infected person's blood, said study researcher James Hughes, of the University of Washington in Seattle.In fact, the amount of virus in the blood is the single most important factor in determining whether HIV is passed between sexual partners, the study found. For every tenfold increase in the concentration, there is about a threefold increase in the risk of transmission during a single sexual act.People with very high blood concentrations of the virus (such as those who very recently acquired the infection) may need to have sex only 10 times to transmit the virus, Hughes said. "The average can be a little deceptive," Hughes said.The new findings reinforce the idea … [Read more...] about HIV Transmission: 1 in 900 Sex Acts Transmits Virus
Even people who don't show symptoms of genital herpes can harbor active forms of the virus that can be spread to sexual partners, according to a new study.People who are infected with the herpes simplex virus type 2, but don't have symptoms, still have active forms of the virus detected on their genital tract 10 percent of the time, the study said.And people who do have symptoms of herpes infection carry active forms of the virus on their genital tract 20 percent of the time, said study researcher Dr. Christine Johnston, acting assistant professor of medicine at the University of Washington.It's long been known that the herpes simplex virus type 2 is contagious even if a person doesn’t have symptoms of the virus, Johnson said. But the new finding shows what percent of the time the virus is actually active and infectious, she added."These findings will help us counsel patients who are diagnosed with [herpes simplex virus type 2] infection about their risks of transmission to … [Read more...] about Sneaky Herpes Virus Lurks Even Without Symptoms