Curious what people are up to when it comes to sex? 
 
 For some of us, not much, according to a new report issued by the Centers for Disease Control and Prevention's National Center for Health Statistics which painstakingly details the country’s sexual habits. 
 
 Based on in-person interviews with approximately 13,500 men and women between the ages of 15 to 44, the report describes who’s having sex with whom, what kind of sex they’re having, and who has yet to become sexually involved. 
 
 Yes, virginity is apparently making a comeback. 
 
 Researchers found that between 2006 and 2008, the percentage of 15- to 24-year-old men who had never had any form of sexual contact with another person was 27 percent (up from 22 percent in 2002) while the percentage of 15- to 24-year-old females who had never had any sex whatsoever was 29 percent (up 7 percent points from 22 percent in 2002). 
 
 Anjani Chandra, a health scientist at the NCHS and lead author of the study, says 15- to 19-year-olds made up the lion’s share of this category, a finding that seems to counter other reports regarding teen sex trends. 
 
 “I think a lot of people misconstrue this as meaning they’ve never had vaginal sex,” she says. “But this is no sexual contact of any kind. They didn’t have oral sex or anal sex. They didn’t have anything.” 
 
 Chandra says she couldn’t speculate as to why there appears to be more virgins in our midst, but said it could be due to sex education, messages about abstinence or that it might hinge on the truthfulness of the respondents. 
 
 “It’s what they’re telling us and we have to take it on faith,” she says. 
 
 Women more likely to have same-sex experiences 
 
 Further data collected from the survey, which asked men and women about their sexual behavior, sexual attraction and sexual identity, found that among adults aged 25 to 44, about 98 percent of females and 97 percent of males have had vaginal intercourse; 89 percent of females and 90 percent of men have had oral sex with an opposite-sex partner; and 36 percent of females and 44 percent of males have had anal sex with an opposite-sex partner. 
 
 The survey also found that women aged 15 to 44 were more than twice as likely to have had a same-sex experience as men of the same age (in 2006-2008, approximately 12.5 percent of women reported a same-sex experience compared with 5.2 percent of men). 
 
 Other data showed that women with four or more sexual partners in their lifetime were more likely to have had a female sexual partner, compared with women who had had no male partners or women who’ve had only one male partner. While the percentage of men and women who reported they were either straight or homosexual was similar, the percentage of women who reported they were bisexual was more than three times as high as men. 
 
 Chandra says one of the things that stood out for her in the report was the same-sex reporting for women. 
 
 “There was speculation that it was possibly just experimentation among college girls but we didn’t see anything to support that,” she says. “We saw the opposite. When we look at college-degreed women, they were less likely to report same-sex activity than other educational groups. Among men, there’s more same-sex activity among higher-educated men. And for women, the highest level of same-sex activity was reported by those with less education.” 
 
 Sexual categories more fluid than thought? 
 
 According to Chandra, data from the survey — which tapped a general household population and did not include high-risk groups such as the homeless or incarcerated — will be used to provide better education and STD prevention efforts. But she says the data is also essential in order to better understand people’s sexual activities and proclivities. 
 
 “It’s important to realize there are not separate groups of sexual people,” she says. “You can’t just think ‘Here are the heterosexual people; here are the homosexual people.’ People draw their partners from all different places. There are not necessarily clear boundaries between the population groups that engage in this behavior or that behavior.” 
 
 Survey data was collected in person by about 40 female interviewers who met one-on-one with participants. Using a laptop, participants would see the question on the screen or listen to a question through a set of headphones. They would then type their answer directly onto the computer, a method that, according to the report, “has been found to yield more complete reporting of sensitive behaviors.” 
 
 The audio for the interview questions – many of them quite explicit (i.e., “Has a male ever put his penis in your rectum or butt — also known as anal sex?”) — was recorded by a female employee of the University of Michigan. 
 
 “We are considering whether we should use a computer-generated voice for future surveys, though,” says Chandra. “Or we might try out ways where a respondent could choose different voices.” ||||| Information about lacking interest in sex was assessed with a single item, asking participants whether they had lacked interest in having sex for a period of ≥3 months in the past year. Those who reported this were also asked whether they experienced associated distress. 
 
 The research questions addressed in this paper are 1 : What sociodemographic, relationship, sexual behaviour and sexual attitudinal factors are associated with lacking interest in sex in sexually active men and women? 2 To what extent do these factors vary by gender? 3 To what extent does lacking interest in sex coexist with other sexual function problems? 
 
 In summary, the evidence on the factors associated with men’s and women’s reports of low sexual desire is drawn largely from non-representative samples, is somewhat equivocal and, in men, sparse. Given that most previous research has involved non-representative samples, it is important to explore how correlates might differ in a population-based sample. Understanding the correlates of lacking interest in sex is key to informing therapeutic options for this group. 
 
 Studies have, for the most part, used small, clinical samples of patients seeking treatment for low sexual desire problems. The potential for bias in such studies is revealed in previously reported findings from Natsal-3 that only around a third of men and women with one or more sexual function problems meeting DSM-5 morbidity criteria had sought professional help in the last year. 2 The few large-scale probability-based surveys involving both men and women have focused on associations between low sexual desire and sociodemographic factors. 
 
 Among women, factors that have been consistently associated with lacking interest in sex are relationship problems, relationship quality and partner’s sexual functioning, 13–17 poor physical health 18 and negative mood states/depression. 13 18 19 There are inconsistent findings on the association between low sexual interest and both age and menopausal status. 14 18 Few large-scale surveys have examined possible links between lacking interest in sex and either sexual attitudes or sexual behaviour. In the second wave of the British National Survey of Sexual Attitudes and Lifestyles (Natsal-2), among women, lacking interest in sex was associated with lower frequency of sex and attitudes according sex low priority. 20 
 
 Most but not all studies involving men have reported an association between low sexual interest and increasing age (for review, see ref. 7 ). However, there are conflicting findings on the association with physical and mental health. 8 9 Limited research suggests that psychosocial and relationship factors may also be associated with low sexual desire in men. 8 10–12 
 
 Researchers have paid more attention to problems of low sexual interest in women than in men. 3–5 Among men the predominant focus has been on erectile functioning and on physiological causes of lacking interest in sex such as hormonal status, rather than on psychosocial determinants. This lack of attention to male problems is reflected in recent revisions to the Diagnostic and Statistical Manual (DSM-5) classification of sexual disorders 6 which involved major changes to sexual arousal and desire disorder categories in women, but no substantive changes for male disorders. 
 
 In Britain’s third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), lacking interest in sex was the most common sexual difficulty reported by both men and women. 1 Lacking interest in sex for ≥3 months in the past year was twice as common in women compared with men. When duration and symptom severity criteria are considered (ie, that symptoms last ≥6 months and occur ‘very often’ or ‘always’), these prevalence estimates are much lower, 2 but the gender difference is maintained. 
 
 All analyses were done using the complex survey functions of STATA V.14 to account for the weighting, clustering and stratification of the data. We used multivariable logistic regression to calculate age-adjusted ORs (AORs) to examine the associations between reports of lacking interest in sex lasting ≥3 months in the past year, and sociodemographic, health, relationship, sexual behaviour and sexual attitude variables. For each variable, we also tested the interaction with gender to see if the magnitude of the associations between the above factors and reports of lacking interest in sex was the same for men and women. We conducted a sensitivity analysis for the outcome variable reporting lack of interest in sex lasting ≥3 months and distress about this symptom to assess whether similar associations were found. We also examined the association between reporting lacking interest in sex and the other sexual function problems asked about in Natsal-3 using AORs. 
 
 Items were drawn from the Natsal-SF, a measure of sexual function, designed and validated for population surveys. The measure comprises items on problems with sexual response, relational aspects of sexual function and self-appraisal of sex life. 23 24 Participants who reported at least one sexual partner in the past year (hereon ‘sexually active participants’) were asked, In the last year, have you experienced any of the following for a period of ≥3 months? and were given a list of difficulties and asked to indicate which they had experienced. The list included Lacked interest in having sex. Those indicating this difficulty were defined as lacking interest in having sex for a period of ≥3 months in the past year (the outcome for this analysis). Individuals reporting lacking interest in sex for at least 3 months were then asked, And how do you feel about this? with response options: not at all distressed, a little distressed, fairly distressed and very distressed. Those answering a little, fairly or very distressed were defined as lacking interest in sex and having distress about this symptom (outcome for sensitivity analysis, see below). 
 
 Only respondents who reported ≥1 sexual partner (opposite-sex or same-sex) in the past year (4839 men and 6669 women) were asked whether they had lacked interest in sex for a period of ≥3 months in the past year (see below). These participants were the focus of the current analyses. 
 
 The estimated response rate was 57.7%, and the estimated cooperation rate (the number of interviews completed from eligible addresses for which contact was made) was 65.8% (of all eligible addressed contacted). 22 More extensive details of the survey methodology and sample characteristics are published elsewhere 21 22 and for demographic characteristics of the sample, see ref. 22 . Participants provided oral informed consent for interviews and the survey was approved by the NRES Committee South-Central— Oxford A (ref.: 10/H0604/27). 
 
 Natsal-3 is a probability sample survey of 15 162 men and women aged 16–74 years in Britain, interviewed between September 2010 and August 2012. A multistage, clustered and stratified probability sample design was used and participants were interviewed in their homes by professional interviewers using a combination of computer-assisted personal interviews and computer-assisted self-interviews (CASIs) for the more sensitive questions (including, of relevance to this paper, those on sexual function). Interviewers were present in the room while participants completed the CASI, but did not view responses. 20 After weighting to adjust for unequal probabilities of selection and to match the British population in terms of age, gender and geographical region, the Natsal-3 sample was broadly representative, on key variables, of the British population as described by the 2011 Census. 21 
 
 Results 
 
 Overall, 15.0% (95% CI 13.9% to 16.2%) of sexually active men and 34.2% (95% CI 32.8% to 35.5%) of sexually active women reported lacking interest in sex for ≥3 months in the year prior to interview. Table 1 presents the associations between lacking interest in sex and sociodemographic, health, relationship, sexual behaviour and sexual attitudinal variables for men and women. 
 
 Table 1 Factors associated with lacking interest in having sex for at least 3 months in the past year in sexually active men and women 
 
 Age was significantly associated with lacking interest in sex. Prevalence increased with age, being lowest among younger participants (16–24 years; men: 11.5%; women: 24.8%) and peaking in men aged 35–44 years (17.2%) and in women aged 55–64 years (38.8%). Regarding demographic variables, after adjusting for age, lack of interest was associated with leaving school at 16 (men only; AOR 1.31), being unemployed (men only; AOR: men: 1.44) and less frequent religious practice (women only; AOR 0.79). In women, after adjusting for age, those who were students or retired were less likely to lack desire. 
 
 After adjusting for age, there were associations between all physical and mental health variables assessed and lacking interest in sex. Individuals in poorer health (AORs: men: 3.29; women: 1.93), those who had much difficulty walking upstairs (AOR: men: 2.68; women: 1.55), those with a long-standing medical condition (AOR: men: 1.76; women: 1.35), and those who had screened positive for current depression (AOR: men: 2.95; women: 2.79) or who had been treated for depression in the past year (AOR: men: 2.82; women: 2.32) were more likely to report lacking interest in sex. The magnitude of these associations was similar for men and women. A greater number of comorbid health conditions was significantly associated with lacking interest in sex among both men and women. Menopausal status in women and circumcision in men were not associated with the likelihood of lacking sexual interest. 
 
 Regarding sexual behaviour, among both men and women, lack of interest was associated with frequency of sexual activity (defined as vaginal, oral or anal intercourse) in the four weeks prior to interview; 12.4% of men and 33.8% of women who reported having engaged in 3–4 sexual acts reported lack of interest versus 20.7% of men and 42.9% of women who reported no sexual activity. Associations with recent masturbation differed by gender; lack of interest in sex was slightly more common among men who reported having recently masturbated but less common among women who did so. Women with three or more partners in the past year were less likely to report low sexual interest than those with only one partner (AOR 0.70) but there was no association between partner numbers and lacking interest in sex in men. Among men only, those who reported ever having taken drugs to assist sexual performance were more likely to report lacking interest in sex (AOR 1.36). A similar magnitude association was seen for women (AOR 1.39); however, fewer women reported ever having taken drugs and the 95% CI therefore crosses 1. 
 
 Associations were found between lacking interest in sex and several relationship contextual variables and for many of these variables associations were stronger for women than for men. For both men and women, lack of interest was associated with relationship status; women living with a partner were more likely to lack interest in sex than those in other relationship categories (see table 1). For women, all relationship categories had lower AORs than living with partner. Duration of most recent sexual relationship was significantly associated with lacking interest in sex only among women, being more common among those in longer relationships. 
 
 Among both men and women, there was an association between ease of communication and lacking interest in sex. Those who found it ‘always easy to talk about sex’ with their partner were less likely to report low interest. Lack of interest was more likely among those whose partner had sexual difficulties in the last year, and those who reported a lower assessment of happiness with the relationship, and not feeling emotionally close to partner during sex. Among women but not men, not sharing the same level of sexual interest with a partner, and not sharing the same sexual likes and dislikes, was also associated. 
 
 Having been pregnant in the last year was associated with lacking sexual interest as was having one or more young child(ren) (women only). Lack of interest in sex was significantly associated with sexual health indicators, including previous sexually transmitted infection (STI) diagnosis and ever having experienced non-volitional sex. The strength and direction of associations was similar for men and women, except for reporting another sexual function problem, which was significant for two or more problems in men, but one or more problems in women. Sexual competence at first sex was significantly associated with lack of interest in sex only among women. 
 
 Regarding attitudinal variables, both men and women who endorsed statements that ‘people are under pressure to have sex’ and ‘people want less sex as they age’ were more likely to report lacking interest in sex over the past year. The only attitudinal variable that showed a significant interaction with gender was that which related to men having a ‘naturally higher sex drive than women’. Men who agreed with this statement were less likely than those who disagreed to lack interest in sex, while the reverse was true among women. 
 
 Table 2 presents the associations between lacking interest in sex and being distressed about this (as a measure/marker of severity), and the above sociodemographic, health and sexual relationship/behaviour variables. While prevalence was lower, the associations and the interactions with gender were generally similar; however, some of the previous gender-specific associations with variables (eg, masturbation, and pregnancy in women, and education in men) were no longer significant when the outcome variable was reported low sexual interest and associated distress. In addition, some associations became stronger when considering only those who reported a distressing lack of interest in sex (vs lack of interest without any reported distress). For example, the association between depressive symptoms and having been treated for depression in the past year was stronger in men than in women. 
 
 Table 2 Factors associated with lacking interest in having sex for at least 3 months in the past year and being distressed about it in sexually active men and women 
 
 Regarding the association between reporting lacking interest in sex and the other sexual function problems asked about in Natsal-3, the strongest (positive) associations were for lacking enjoyment in sex (AOR 9.78 and 8.95 for men and women, respectively), followed by feeling no excitement or arousal during sex (AOR 9.21 and 9.16 for men and women, respectively) (see table 3).
– A new federal study suggests more young men and women are remaining virgins longer. In the 15-24 age group, 27% of men and 29% of women say they've never had a sexual encounter of any kind, reports MSNBC. That's up from 22% for both groups from the last study in 2002. Other findings: In the 25-44 age group, 97% of men and 98% of women have had vaginal intercourse, and about 90% in both groups have had oral sex, notes the Washington Post. 36% of women and 44% of men in the age group have had anal sex. 12.5% of women reported a same-sex experience, vs. 5.2% of men. 21% of men say they've had at least 15 sex partners, compared with 8% of women. To read about Northwestern's hey-watch-this approach to sex ed, click here.