SciCombinator

Background Serum testosterone concentrations decrease as men age, but benefits of raising testosterone levels in older men have not been established. Methods We assigned 790 men 65 years of age or older with a serum testosterone concentration of less than 275 ng per deciliter and symptoms suggesting hypoandrogenism to receive either testosterone gel or placebo gel for 1 year. Each man participated in one or more of three trials - the Sexual Function Trial, the Physical Function Trial, and the Vitality Trial. The primary outcome of each of the individual trials was also evaluated in all participants. Results Testosterone treatment increased serum testosterone levels to the mid-normal range for men 19 to 40 years of age. The increase in testosterone levels was associated with significantly increased sexual activity, as assessed by the Psychosexual Daily Questionnaire (P<0.001), as well as significantly increased sexual desire and erectile function. The percentage of men who had an increase of at least 50 m in the 6-minute walking distance did not differ significantly between the two study groups in the Physical Function Trial but did differ significantly when men in all three trials were included (20.5% of men who received testosterone vs. 12.6% of men who received placebo, P=0.003). Testosterone had no significant benefit with respect to vitality, as assessed by the Functional Assessment of Chronic Illness Therapy-Fatigue scale, but men who received testosterone reported slightly better mood and lower severity of depressive symptoms than those who received placebo. The rates of adverse events were similar in the two groups. Conclusions In symptomatic men 65 years of age or older, raising testosterone concentrations for 1 year from moderately low to the mid-normal range for men 19 to 40 years of age had a moderate benefit with respect to sexual function and some benefit with respect to mood and depressive symptoms but no benefit with respect to vitality or walking distance. The number of participants was too few to draw conclusions about the risks of testosterone treatment. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00799617 .).

Zika virus infection has been linked to increased risk for Guillain-Barré syndrome and adverse fetal outcomes, including congenital microcephaly. In January 2016, after notification from a local health care provider, an investigation by Dallas County Health and Human Services (DCHHS) identified a case of sexual transmission of Zika virus between a man with recent travel to an area of active Zika virus transmission (patient A) and his nontraveling male partner (patient B). At this time, there had been one prior case report of sexual transmission of Zika virus (1). The present case report indicates Zika virus can be transmitted through anal sex, as well as vaginal sex. Identification and investigation of cases of sexual transmission of Zika virus in nonendemic areas present valuable opportunities to inform recommendations to prevent sexual transmission of Zika virus.

Adolescence is marked by the emergence of human sexuality, sexual identity, and the initiation of intimate relations; within this context, abstinence from sexual intercourse can be a healthy choice. However, programs that promote abstinence-only-until-marriage (AOUM) or sexual risk avoidance are scientifically and ethically problematic and-as such-have been widely rejected by medical and public health professionals. Although abstinence is theoretically effective, in actual practice, intentions to abstain from sexual activity often fail. Given a rising age at first marriage around the world, a rapidly declining percentage of young people remain abstinent until marriage. Promotion of AOUM policies by the U.S. government has undermined sexuality education in the United States and in U.S. foreign aid programs; funding for AOUM continues in the United States. The weight of scientific evidence finds that AOUM programs are not effective in delaying initiation of sexual intercourse or changing other sexual risk behaviors. AOUM programs, as defined by U.S. federal funding requirements, inherently withhold information about human sexuality and may provide medically inaccurate and stigmatizing information. Thus, AOUM programs threaten fundamental human rights to health, information, and life. Young people need access to accurate and comprehensive sexual health information to protect their health and lives.

Alcohol consumption is known to be associated with risky sexual behaviours, but this relationship may be complex and bidirectional. We explored whether alcohol consumption leads to the consumer being rated as more attractive than sober individuals.

In December 2013, during a Zika virus (ZIKV) outbreak in French Polynesia, a patient in Tahiti sought treatment for hematospermia, and ZIKV was isolated from his semen. ZIKV transmission by sexual intercourse has been previously suspected. This observation supports the possibility that ZIKV could be transmitted sexually.

Sex and disgust are basic, evolutionary relevant functions that are often construed as paradoxical. In general the stimuli involved in sexual encounters are, at least out of context strongly perceived to hold high disgust qualities. Saliva, sweat, semen and body odours are among the strongest disgust elicitors. This results in the intriguing question of how people succeed in having pleasurable sex at all. One possible explanation could be that sexual engagement temporarily reduces the disgust eliciting properties of particular stimuli or that sexual engagement might weaken the hesitation to actually approach these stimuli.

Concern about young people’s sexuality is focused on the need to prevent harmful outcomes such as sexually transmitted infections and unplanned pregnancy. Although the benefit of a broader perspective is recognized, data on other aspects of sexuality, particularly sexual function, are scant. We sought to address this gap by measuring the population prevalence of sexual function problems, help seeking, and avoidance of sex in young people.

Human reproduction does not happen uniformly throughout the year and what drives human sexual cycles is a long-standing question. The literature is mixed with respect to whether biological or cultural factors best explain these cycles. The biological hypothesis proposes that human reproductive cycles are an adaptation to the seasonal (hemisphere-dependent) cycles, while the cultural hypothesis proposes that conception dates vary mostly due to cultural factors, such as holidays. However, for many countries, common records used to investigate these hypotheses are incomplete or unavailable, biasing existing analysis towards Northern Hemisphere Christian countries. Here we show that interest in sex peaks sharply online during major cultural and religious celebrations, regardless of hemisphere location. This online interest, when shifted by nine months, corresponds to documented human births, even after adjusting for numerous factors such as language and amount of free time due to holidays. We further show that mood, measured independently on Twitter, contains distinct collective emotions associated with those cultural celebrations. Our results provide converging evidence that the cyclic sexual and reproductive behavior of human populations is mostly driven by culture and that this interest in sex is associated with specific emotions, characteristic of major cultural and religious celebrations.

To assess the effect of a combination strategy for prevention of human immunodeficiency virus (HIV) on the incidence of HIV infection, we analyzed the association between the incidence of HIV and the scale-up of antiretroviral therapy (ART) and medical male circumcision in Rakai, Uganda. Changes in population-level viral-load suppression and sexual behaviors were also examined.

The motivational incentive of reward-related stimuli can become so salient that it drives behavior at the cost of other needs. Here we show that response inhibition applied during a Go/No-go task not only impacts hedonic evaluations but also reduces the behavioral incentive of motivationally relevant stimuli. We first examined the impact of response inhibition on the hedonic value of sex stimuli associated with strong behavioral-approach responses (Experiment 1). Sexually appealing and non-appealing images were both rated as less attractive when previously encountered as No-go (inhibited) than as Go (non-inhibited) items. We then discovered that inhibition reduces the motivational incentive of sexual appealing stimuli (Experiment 2). Prior Go/No-go status affected the number of key-presses by heterosexual males to view erotic-female (sexually appealing) but not erotic-male or scrambled-control (non-appealing) images. These findings may provide a foundation for developing inhibition-based interventions to reduce the hedonic value and motivational incentive of stimuli associated with disorders of self-control.