Prevalence, Frequency, and Associations of Masturbation With Partnered Sexual Behaviors Among US Adolescents FREE

Masturbation carries no risk of pregnancy or sexually transmitted infections and may have benefits to sexual and emotional health.^1- 2 While one major study of male and female college students found no association, positive or negative, between a history of masturbation during early adolescence and sexual satisfaction during young adulthood,³ other studies have shown positive relationships. Among women, masturbation in childhood and adolescence has been associated with positive sexual experiences later in life⁴ and a healthy self-image.⁵ In another study of adolescent females aged 16 to 18, those with negative or indifferent views about masturbation reported negative first sexual experiences compared with those who held positive views of masturbation.⁶

Masturbation is thought to be a common behavior. In studies of older adolescents and adults, masturbation is nearly universal among males and reported by a majority of females.^7- 11 In an Australian study, 58% of males and 42% of females aged 15 to 18 years reported at least 1 lifetime episode of masturbation.² Masturbation onset was found to occur by age 13 years in 53% of males and 25% of females in another retrospective study.¹² Also, in a recent national sample of sexual behaviors in the United States (from which data for the current study were obtained), masturbation was more common than any partnered sexual behavior among 14- to 17-year-old adolescents.¹³

Despite its apparent widespread prevalence, masturbation is a highly stigmatized topic viewed negatively across settings. In research on sexual behavior, masturbation is among the most sensitive topics, and underreporting by adolescents has been found even with the use of confidential reporting techniques.¹⁴ Although not universal in all denominations or branches of the world's major religions, guilt, shame, and indulgence continue to be themes all religions associate with masturbation.^15- 16 The public often views masturbation negatively as well. In the popular media, masturbation is often the subject of jokes.^17- 18 In 1994, when US Surgeon General Joycelyn Elders recommended including masturbation as a topic in public sexual education, she was heavily criticized and ultimately resigned.¹⁹ The Sexuality Information and Education Council of the United States (SIECUS) guidelines on sexuality education include masturbation as a key topic,²⁰ but masturbation is often omitted from sexuality education²¹ even in the context of abstinence-only education.²² Parents report having difficulty discussing masturbation with their adolescent children, some with the hope that their children will view masturbation unfavorably.^23- 25 Notably, health care providers also omit discussion of masturbation: in a study where 64% of parents with children aged 12 years or older recalled discussions with their health care provider on sexuality, only 6% of discussions addressed masturbation.²⁶

Improved understanding of masturbation is critical to a comprehensive understanding of healthy adolescent sexual development. In the current study, masturbation frequency and the association between masturbation and other sexual health behaviors and condom use were assessed in a representative sample of American adolescents. Such understanding informs clinical approaches for addressing concerns about masturbation and demonstrates potentially important linkages between masturbation and other sexual health behaviors.

Data were obtained from The National Survey of Sexual Health and Behavior (NSSHB), a population-based cross-sectional survey, to assess solo and partnered sexual behaviors conducted from March 2009 through May 2009 among adult and adolescent participants recruited via Knowledge Networks research panels (Menlo Park, California).¹³ Knowledge Networks panels were established based on random-digit dialing methods and address-based sampling. Randomly selected addresses were recruited to research panels through mailings with telephone follow-ups to nonresponders when possible. Once the panels were established, adults within a panel received a recruitment message from Knowledge Networks providing a description of the NSSHB and an invitation to participate. Individuals who agreed to participate were provided with computer hardware and access to the Internet, if needed. All questionnaire data were collected by Knowledge Networks via the Internet. Data obtained via Knowledge Networks have been used in other health-related studies, substantiating the validity of such methods for obtaining data from nationally representative samples of the US population.²⁷

Recruitment included adolescent participants as well as their parents or guardians. A total of 2172 parents and guardians reviewed a description of the study (including the questionnaire): 62% consented to allow their child to be invited via e-mail to participate (n = 1347), 61% of invited adolescents responded (n = 831), and 99% of responding adolescents consented to participate (n = 820) (37% overall participation rate). All study protocols were approved by the institutional review board of Indiana University.

Data regarding gender, age, race/ethnicity, region of residence, education level, and family income were obtained from Knowledge Networks' participant files. The sample was stratified to the December 2008 Current Population Survey US census update.²⁸ Poststratification data weights were used to make population-based estimates within gender, age, and race/ethnicity classifications.

Prevalence and frequency of masturbation was assessed in the context of inquiry about a variety of other sexual behaviors. Specifically, participants were presented with a list of sexual behaviors and asked “Have you done any of the following?” The subsequent cue relevant to masturbation read “I masturbated alone (stimulated your body for sexual pleasure, whether or not you had an orgasm).” This item addressed specific time periods: past 3 months, past year, and lifetime. Participants reporting masturbation either in the past 3 months or past year were subsequently asked “On average, during the past 12 months, about how often did you masturbate alone?” Response options included “a few times per year,” “a few times per month,” “2-3 times per week,” or “4 or more times per week.”

Specific sexual behaviors requiring a partner were assessed over the past year. Male and female participants were asked “Have you done any of the following?” and presented with the following sexual behaviors: “A female gave me oral sex (gave me head)”; “A male gave me oral sex (gave me head)”; “I gave oral sex to a female (I gave head)”; “I gave oral sex to a male (I gave head)”; “I masturbated with another person”; “Someone put their penis in my anus (butt)”; and “I had vaginal intercourse (penis in vagina).” Male participants were also asked about the following: “I put my penis in someone's anus (butt).”

In addition, participants were also asked if the indicated partnered sexual behaviors occurred during their most recent sexual experience (answering yes/no for each behavior). If participants answered that they had penile-vaginal intercourse or insertive or receptive anal sex during their most recent sexual experience, they were then asked “Which of the following about the use of a condom during this act of intercourse applies?” Condom use was recorded if the participant answered yes to the following statement: “we used a condom at some point during this sexual act.”

Separate analyses were conducted for adolescent men and women. All analyses were conducted using SPSS version 17.0 (SPSS Inc, Chicago, Illinois). Poststratification data weights were used during all analyses to maximize the generalizability of the sample characteristics to the population. Poststratification adjustments were based on current census data on national distributions for age, gender, race/ethnicity, education, and location within the United States. Descriptive statistics were used to calculate the proportion of adolescents reporting masturbation at any given time period and the distribution of responses by demographic variables, partnered sexual behaviors, and condom use. Approximate 95% confidence intervals were calculated using the adjusted Wald method.

Among the study sample, 50.5% were males (n = 414), 49.5% were females (n = 406), and race/ethnicity, education, family income, and geographic residence distribution reflected the US adolescent population (Table 1). Sexual orientation was self-identified as heterosexual for most participants (93.3%). Approximately half of all participants identified themselves as currently being in a romantic relationship (46.7% of males and 45.6% of females).

Masturbation prevalence, both lifetime and in the past 90 days, was higher in males than females in all age groups (Table 2). Among males, at age 14 years, 62.6% reported ever having masturbated, while 72.7% of 15-year-olds, 78.1% of 16-year-olds, and 80% of 17-year-olds reported ever having masturbated. Among females, 43.3% of 14-year-olds reported a past experience of masturbation; this percentage did not change much until age 17 years, when it was found that 58% had ever masturbated. Although similar numbers of males and females reported masturbation in the past 90 days at age 14 years (42.9% of males and 36.7% of females), the percentage of males who indicated recent masturbation was higher in every subsequent age group, while recent masturbation showed little variation among age groups in females.

Masturbation frequency was also higher among males than females, but no trends by age were apparent for either gender (Table 3). When asked about masturbation frequency in the past year, approximately half of male participants reported masturbation at least twice weekly (49.1%). Among females, 45.5% reported masturbation a few times per year, while only 22.5% reported masturbation frequencies of at least 2 times a week.

Solo masturbation in the past year was associated with partnered sexual behavior among both males and females (Table 4). Males reporting masturbation in the past year were more likely to have engaged in partnered sexual activity (odds ratio [OR], 4.2), and significant associations existed with penile-vaginal intercourse (OR, 4.3), giving oral sex (OR, 4.1), and receiving oral sex (OR, 3.0). Among females, engaging in solo masturbation was also associated with partnered sexual activity (OR, 4.5) including partnered masturbation (OR, 8.4), giving oral sex (OR, 5.5), receiving oral sex (OR, 3.2), penile-vaginal intercourse (OR, 2.1), and anal intercourse (OR, 14.0).

Because masturbation may be associated with increased sexual self-awareness, we explored potential associations between masturbation in the past year and condom use among adolescents reporting penile-vaginal intercourse for their most recent partnered sexual event. Condom use was associated with solo masturbation in males but not females (Table 5). Among males who reported penile-vaginal intercourse during their last sexual event, masturbation in the past year was associated with condom use (OR, 8.5). The small number of adolescents reporting anal sex precluded analysis of condom use during this sexual event, and condom use during oral sexual encounters was not inquired about.

This article presents data on the prevalence, frequency, and sexual behavior correlates of masturbation in a national sample of adolescents in the United States as part of a larger survey of sexual behavior and condom use. In both males and females, masturbation is a commonplace experience of adolescent sexual development. In addition to the high prevalence of masturbation, the association of masturbation with other sexual behaviors makes it an important factor in adolescent sexuality.

This research reports that prevalence and frequency of masturbation differs markedly between males and females throughout adolescence. Gender differences in masturbation are among the largest and most consistent of any aspect of sexual behavior.²⁹ Reasons for these large gender differences are not well understood. Primate studies suggest that regular masturbation maintains semen and sperm quality,³⁰ and regular masturbation together with nocturnal emissions has been suggested to maintain sperm quality in humans as well.³¹ Differences in brain organization related to sexual arousal and androgenic hormonal influences may also play a role.^32- 33 Genital anatomical differences in pleasure sensation between males and females may also explain why masturbation is less common in females.³⁴ Additionally, masturbation onset has been found to be associated with pubertal onset in males but not in females, suggesting that hormonal influences on masturbation differ among males and females.³⁵ Finally, strong influences of society and culture, best expressed by a sexual double standard that condones male sexual expressions and suppresses female sexuality, are also likely.³⁶ Such influences would appear to affect male and female participants differently in their responses to questions on their own masturbation as well, perhaps accounting for some of the observed gender differences in masturbation.

The association of masturbation with other sexual behaviors indicates that masturbation is an important component of adolescent sexuality rather than an isolated or transient phenomenon. Our cross-sectional data cannot address whether masturbation typically precedes or follows initiation of other sexual behaviors. However, masturbation appears to endure even as other sexual behaviors develop and is one way adolescents experience sexuality. Thus, dismissing masturbation as a developmental phase misconstrues its role throughout adolescent sexuality.

Notably, masturbation was associated with higher condom use rates in adolescent males. While this association was found in a subsample of the participants, the association of any behavior with increased condom use deserves further investigation, given the rates of unintended pregnancies and sexually transmitted infections in adolescents.³⁷ Masturbation has long been promoted as a means to greater body awareness, perhaps explaining the association of condom use with masturbation in males but not females.

Our findings represent the most recent and comprehensive investigation on adolescent masturbation in the United States. A few points, however, should be noted when interpreting these data. These findings represent masturbation prevalence, frequency, and associations with other sexual behaviors. No conclusions can be made on why adolescents masturbate or the exact role masturbation plays in adolescent sexuality and sexual development, areas deserving of future research. In addition, the interactions of masturbation and sexual development is a dynamic process during childhood and adolescence. Because our youngest participants were 14 years old, and at this age a high proportion of males and females reported masturbation, further investigations should include younger ages to provide a more complete picture of masturbation in childhood and adolescence. With inclusion of younger ages, and even the 14-year-olds in this study, attention should be given to the participants' comprehension of the word masturbation. We attempted to define masturbation (by asking “Have you stimulated your body for sexual pleasure?”), but defining masturbation involves the assumption that participants understand complex concepts such as sexual pleasure, and it is possible that some 14-year-olds and younger adolescents will not understand such concepts regardless of the definition. In addition, male and female adolescents may comprehend the same description of masturbation differently based on how they experience sexual pleasure, possibly explaining some of the gender differences seen in our data.

Finally, a volunteer bias may exist, in that first parents and then the adolescents had to agree to participate in a study on sexuality, with 62% of parents consenting after reading a description of the study and 61% of invited adolescents responding to the initial e-mail. Responding adolescents and those families who agreed to allow their child to participate in a study on sexual behavior may differ from nonresponding adolescents and families who declined. While data on those who did not agree to participate are unavailable, sampling procedures were used to minimize potential sociodemographic differences. Because the sexual behavior of those who did not consent or respond is unknown, we cannot analyze sexual behavior differences between these groups to estimate the size of this bias.

Professional organizations such as the American Academy of Pediatrics and the American College of Obstetrics and Gynecology recognize masturbation as a normal component of child and adolescent development and recommend that health care providers educate their patients on masturbation as part of discussions on sexuality during preventative health visits throughout childhood, beginning in the preschool years.^38- 40 Because of the prevalence, frequency, and associations of masturbation with other sexual behaviors, its omission as a core component of adolescent sexuality limits our clinical capacity to fully understand and address adolescent sexual development. Adolescents may receive information about masturbation in school and from parents, but an informal Google search on “questions about masturbation on websites for adolescents” indicates that many questions remain. Well-informed health care providers with the authority of clinical medicine and the capacity to provide greater privacy, individualized discussions, and the ability to respond to questions confidentially play an important role in adolescents' sexuality education. The findings of this study together with existing publications on masturbation should be used by health care providers to inform, educate, and reassure adolescents about masturbation to provide competent and comprehensive sexuality education in the clinical setting.