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As researchers and community-based providers continue to encourage latex condom use as a chief strategy to prevent HIV transmission among men who have sex with men, research is needed to better explore the intersecting associations among penis size (length and circumference), condom feel, ease of finding condoms, recent experience of condom failure (breakage and slippage), and unprotected anal sex. Data were taken from a 2010 community-based survey of self-identified gay and bisexual men in New York City (n = 463). More than half (51.4 %) reported penile length as 6-8 in. long (15-20 cm) and 31.5 % reported penile circumference as 4-6 in. around (10-15 cm). Variation in self-reported penile dimensions was significantly associated with men's attitudes toward the typical/average condom, difficulty finding condoms that fit, and the experience of condom breakage. Men who had engaged in recent unprotected insertive anal intercourse reported significantly higher values for both penile length and circumference, and these men were significantly more likely to report that the average/typical condom was "too tight." Most men had measured their length (86.2 %) and/or circumference (68.9 %), suggesting that penile measurement might be a common and acceptable practice among gay and bisexual men. As HIV and STI prevention providers continue to serve as leading distributers of free condoms, these findings further highlight the need for condom availability to be in a variety of sizes. Improving condom fit and attitudes toward condoms may also improve condom use and minimize condom slippage and breakage.

Larger penis size has been equated with a symbol of power, stamina, masculinity, and social status. Yet, there has been little research among men who have sex with men assessing the association between penis size and social-sexual health. Survey data from a diverse sample of 1,065 men who have sex with men were used to explore the association between perceived penis size and a variety of psychosocial outcomes. Seven percent of men felt their penis was "below average," 53.9% "average," and 35.5% "above average." Penis size was positively related to satisfaction with size and inversely related to lying about penis size (all ps < .01). Size was unrelated to condom use, frequency of sex partners, HIV status, or recent diagnoses of HBV, HCV, gonorrhea/Chlamydia/urinary tract infections, and syphilis. Men with above average penises were more likely to report HPV and HSV-2 (Fisher's exact p

Men and women living in New Zealand and California completed five studies regarding human physique and sexual attractiveness. In Studies 1-3, women rated images of male stimuli and, in Studies 4-5, men rated female stimuli. In Study 1, women in both countries rated mesomorphic (muscular) and average male somatotypes as most attractive, followed by ectomorphic (slim) and endomorphic (heavily built) figures. In Study 2, amount and distribution of masculine trunk hair (chest and abdominal) was altered progressively in a series of front-posed male figures. In both countries, the image lacking any trunk hair was rated as the most attractive, with a steady decline in attractiveness as hirsutism became more pronounced. Study 3 assessed attractiveness of front-posed male figures that varied only in the length of the non-erect penis. Five lengths were presented: The smallest penile size was rated as less attractive than three intermediate sizes. The largest penile size was not the most attractive, but received higher scores than the unaltered and smallest penile size. In Study 4, men rated the attractiveness of back-posed female images varying in waist-to-hip ratio (WHR) (from 0.5 to 1.0). The 0.7 WHR figure was rated more attractive in New Zealand and the 0.6 WHR in California. Study 5 measured the attractiveness of female skin color; men expressed preferences for lighter skinned female figures in New Zealand and California. Results indicate very similar preferences for sexually dimorphic physical traits among men and women of European extraction, living in two culturally and geographically different environments.

Both physiological and self-measurement methods have been employed to collect data on the dimensions of the erect penis. However, self-measurement using paper strips has often been favored as a less intrusive and time-consuming method, despite the recognition of the increased chance of bias through exaggeration. The current study aimed to establish the test-retest reliability of measurement of the erect penis using paper strips in a sample of 312 gay men. The men were issued with color-coded measuring strips printed with instructions but no calibrations, and asked to measure both the length and circumference of their partners' erect penis. Three months later they were asked to repeat these measures. Mean length on first measurement was 15.3 cm and 15.2 cm on second measurement. Mean girth at first measurement was 12.5 cm and 12.6 cm at second measurement. Test-retest reliability of measurement was found to be moderately low at r = .60 for length and r = .53 for girth. No relation was found between measurement discrepancy and the age, social class, education, ethnicity, or employment status of the partner taking the measurements. Although self-measurement strips are both convenient and acceptable, and widely reported in the literature, they only have moderate test-retest reliability. This may be due to both natural variability in penis size within subjects over time and unreliability of the measurement method.

The relation between sexual orientation and penile dimensions in a large sample of men was studied. Subjects were 5122 men interviewed by the Kinsey Institute for Research in Sex, Gender, and Reproduction from 1938 to 1963. They were dichotomously classified as either homosexual (n = 935) or heterosexual (n = 4187). Penile dimensions were assessed using five measures of penile length and circumference from Kinsey's original protocol. On all five measures, homosexual men reported larger penises than did heterosexual men. Explanations for these differences are discussed, including the possibility that these findings provide additional evidence that variations in prenatal hormonal levels (or other biological mechanisms affecting reproductive structures) affect sexual orientation development.

Functional relationships between the penis, vagina, and cervix during copulation in the chimpanzee were studied. In 11 adult males, penile length during full erection ranged from 10.0-18.0 cm (mean +/- SD = 14.4 +/- 2.02). In 19 parous adult females examined during the early follicular phase of the cycle, or during lactation, vaginal depth (from the introitus to the os cervix) ranged from 9.8-16.5 cm (mean +/- SD = 12.6 +/- 1.69). However, when the sexual skin was maximally swollen, vaginal depth increased by up to 52% in some cases and ranged from 15.2-20.1 cm (mean +/- SD = 16.9 +/- 1.68). Under such conditions males vary in their ability to achieve maximal depth of intromission. Observations made on 6 females after natural matings revealed that in some cases males had deposited copulatory plugs in contact with the cervix, while in others plugs were lower down in the vagina. Direct observations under fluoroscopy using an artificial "penis" loaded with radio-opaque medium showed that the filiform tip can make contact with the os cervix. However, expulsion of radio-opaque medium under these conditions failed to demonstrate any immediate transfer of fluid through the cervix into the uterus. These studies indicate that, aside from its functions as a visual signal, the female chimpanzee's sexual skin swelling adds considerably to the distance males must negotiate during copulation to place spermatozoa at the cervical os. Evolution of the male's elongated, filiform penis may therefore be the result of sexual selection, to negotiate the long vagina of the female and to penetrate copulatory plugs deposited during previous copulations.

Two experiments were conducted testing reliability of expansion chamber determined gauge element breakage ranges; 20 trials with sexually functional males provided comparative data on the gauge in actual application. Circumference of the expansion chamber and increases in penile circumference were simultaneously monitored via a mercury strain gauge. Results for both experiments indicated considerable overlap at gauge element breakpoints, and yielded an overall misdiagnosis rate of 15.5% in a young, healthy population.

With the acceptance of behavior modification techniques in the 1970's as the standard modality of treatment of sex offenders, the ability to diagnose the paraphilic arousal patterns became of primary importance. The use of the penile plethysmograph in the assessment of sex offenders is regarded as the most accurate measure of these sexual arousal patterns. This method measures the vasocongestive engorgement of the penile corporea while the offender is exposed to deviant and nondeviant sexual stimuli. The stimuli may be slides of nude males and females of varying ages, audiotaped descriptions of erotic scenarios or videotaped scenes of sexual interaction. Researchers who have used slides to determine the age and gender preference of the sex offenders have typically categorized the slides in arbitrarily established age categories that have varied from one research study to another. The use of age as a criterion does not take into account the variation in growth and maturation among children and adolescents. To increase reliability and standardization of research techniques, the authors propose that the stages of sexual maturity as set forth by Tanner (1962, 1978) be used in lieu of age.

Objective measurements of sexual arousal in men most commonly involve monitoring changes in penile size. Although changes in circumference are most often used, volumetric changes have been reported to be more sensitive and thus more effective. Six men volunteered to observe an erotic videotape while circumferential and volumetric changes of their penises were recorded. The two measures were significantly correlated (r = .68) but the volumetric device was more difficult to use, displayed considerably more artifacts, and was not more sensitive than a mercury-in-rubber strain gauge.