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

Survey: People Over 70 Are Still at It

A survey of over 7,000 UK adults found that sex is not exclusively for the young. Among respondents over 70, more than half of the men (54 percent) and almost a third of the women (31 percent) describe themselves as sexually active. A third of these sexually active adults say they have frequent sex, which was defined as more than twice a month.

These findings are similar to those of surveys conducted here in the United States. A 2007 study, for example, found that 53 percent of respondents between 65 and 74 were sexually active, as were 26 percent of respondents between 75 and 85. A 2010 study from AARP also found that 15 percent of men and 5 percent of women 70 and over had sex at least once a week, and an additional 7 percent of men and 6 percent of women this age had it once or twice a month.

The authors of the new study hope their findings will help change misperceptions about sex as we age. As they explain to the Huffington Post, “We hope our findings improve public health by countering stereotypes and misconceptions about late-life sexuality, and offer older people a reference against which they may relate their own experiences and expectations.”

Of course, older adults who are having sex have some of the same issues as their children and perhaps grandchildren, as rates of sexually transmitted infections are rapidly rising in older adults both here and in the UK.

Early Menstruation Linked to Sugary Drinks

Researchers at Harvard Medical School released a study last week showing a correlation between the number of sugary drinks a young girl consumes and the age at which she gets her first period.

They followed 5,583 girls ages 9 to 14 who had not yet started menstruating and collected numerous pieces of information about their physical fitness and diet. They found that girls who drank more than 1.5 servings of sugar-added drinks (such as sodas or fruit-ades) per day started their periods an average of 2.7 months earlier than girls who drank fewer than two servings a week.

The interesting thing is that this link between the drinks and menstruation survived even when the researchers controlled for other obvious factors such as height, birth weight, and physical activity.

Though the study does not show that these drinks cause earlier menarche, the researchers provide one explanation for how they could: Sugar can cause spikes in insulin, which in turn can increase the level of sex hormones (estrogen and progesterone) in the body. These hormones control menstruation. The authors say that past research on insulin has found a connection to menstruation—girls who have Type I diabetes and don’t make sufficient insulin, for example, often start their periods later than their peers. Of course, more research is needed to confirm the connection.

Though the age of the onset of puberty in girls has been dropping in recent decades, the age of first period has dropped very little. Still, experts are concerned about those who develop earlier than average for both medical and social reasons. Most notably, puberty marks a girl’s final growth spurt; those who enter it earlier have fewer total years to grow and may end up shorter than their peers who start puberty later.

Condoms Set to Walk the Runway

Fans of Project Runway will likely remember the unconventional materials challenge, where designers are given things other than fabric—from candy to recycling—and told to make a stunning runway look. On February 10, students at Central Washington University will do something similar, creating looks out of a very unconventional material: condoms.

The university’s Wellness Center reportedly said it hopes “putting sexual health on the catwalk … [will] reduce the discomfort of discussing condoms and sexual health.”

Fifteen teams will compete, and each will be given 600 condoms with which to complete a look that is not only fashionable but has a sexual health-related theme (that goes beyond condoms). As an example, Doug Fulp, a health educator at the university, said he saw a similar fashion show in Montana in which a team titled their design “Guard Against HPV” and dressed their model like a lifeguard.

We can’t imagine Heidi Klum saying auf Wiedersehen to a lifeguard dressed in condoms, can you?