A number of studies have demonstrated that a high proportion of male homosexuals will at some time engage in a stable relationship [1–4], and it has been shown that the non-use of condoms is more frequent with steady than with casual partners [5–7]. The management of risk of HIV infection within male homosexual steady relationships (hereafter referred to as ‘the gay couple') has thus emerged as a major concern for prevention [8,9]. Research interest has focused on ‘negotiated safety’, which has been shown to be both feasible and effective , although not without risks [12,13]. ‘Negotiated safety’ holds that the risk of infection can be managed within a couple, provided specific conditions are met: both partners in the couple have been tested and have been shown to be HIV negative, they have discussed it together, and are monogamous or always use condoms with casual partners, or do not practise anal sex with them. However attractive this strategy may be, it is demanding and may not, in practice, be the preferred choice of homosexual couples. Agreements about the management of HIV risk within the gay couple can take many forms, some without the risk of infection, others entailing varying levels of risk [11,14,15].
This article focuses on the management of HIV risk specifically within the gay couple. It compares the characteristics of respondents in a stable relationship with those in none, and describes: the stated means of managing HIV risk within the gay couple; the sexual and protective practices with the steady and with possible casual partners, and the relationship between these practices and HIV status; factors associated with consistent condom use with the steady partner. It is based on information obtained by questionnaire survey from respondents who reported having a steady partner within the last 12 months. Completed in 1997, this study is part of the ongoing evaluation of AIDS prevention among homosexuals in Switzerland [16,17], the fifth such survey since 1987 [18–21]. The proportion of respondents reporting a steady partner in the course of the past 12 months has increased steadily since 1992, and there has been an increase in the practice of anal penetration with casual partners. No change has been observed in the number of partners or the frequency of sexual relations . Overall trends are reported more fully in a forthcoming paper. Information on strategies for the management of risk in the gay couple presented here comes from an additional module, developed on the basis of results from a qualitative study exploring the dynamics of couple communication, specifically introduced into this last survey .
Between May and August 1997, an anonymous questionnaire consisting of 54 questions was placed in four gay newspapers in the German-speaking and French-speaking regions of Switzerland and was distributed in gay organizations, bars, and saunas. Most replies were obtained through the press (56%) or organizations (34%). The following topics were included:
•social and demographic characteristics of the respondents;
•number of partners over the previous 12 months;
•with both the steady partner and with casual partners: sexual practices, the use of condoms during anal sex over the past 12 months and at last intercourse, semen in the mouth during oral sex;
•community and social life: membership of gay or AIDS organizations, frequenting of different homosexual meeting-places;
•frequency (regularly, sometimes, never) of drug use (alcohol, cannabis, heroin, cocaine, crack, ecstasy, poppers);
•HIV testing: previous test history and serological status of the respondent;
•characteristics of the steady partnership: occurrence of a steady partnership within the preceding 12 months, reported exclusivity of the relationship, duration of the partnership, and degree of anxiety concerning the risk of HIV infection in the couple;
•characteristics of the steady partner: his age, previous test history and serological status, possible casual partners over the preceding 12 months;
•management of HIV risk: reported strategies for the management of HIV risk within the couple, existence and content of agreement reached within the couple on HIV risk management with possible casual partners.
No one definition of a ‘steady’ relationships is to be found in the literature; criteria vary in terms of the duration of the relationship, whether partners lived together, the sense of commitment etc. [11,14,24,25]. In the present study, the respondent's perception was considered the most pertinent and valid criterion, and hence the definition of a ‘steady’ partner was left to the appreciation of the respondent, as was the definition of an ‘exclusive’ relationship.
The methods of analysis used were contingency tables and logistic regression with the SPSS statistical package; 95% confidence intervals were used to ascertain parameter estimates.
Characteristics of the overall sample
A total of 1097 questionnaires was obtained. The characteristics of the sample are shown in Table 1. The average age was 36.7 years (median age 34); the educational level was high, 28% having attended university or a polytechnic college (as compared with 13% in the Swiss male general population ). The majority lived in one of the five major Swiss cities, and more than half lived alone. One-third had joined a gay organization and one-tenth an AIDS organization. Over 80% had had more than one sexual partner during the year, and 74% (n = 786) of respondents reported having had a steady partner over part or all of the preceding 12 months. Among the 81% who had been tested for HIV, 11% were HIV positive.
Characteristics of respondents reporting a steady partner over the previous 12 months
As compared with respondents reporting no steady partner over the past 12 months, respondents replying that they had had a steady partner were younger and had had fewer partners. They were more sexually active, 41% reporting sexual relations several times a week, compared with 12% of those having had no such relationship. They were more likely to socialize with heterosexuals as well as homosexuals; their homosexuality was more often known and better accepted by their parents and colleagues, and fewer reported having no friends (data not shown).
There was a wide variation in age difference between partners, almost half the couples having a difference of 6 years or more. The sample was relatively well balanced regarding the inclusion of both the older and the younger of the partners (the difference in respondents mean age relative to reported mean age of partners was 1.5 years). A wide range of lengths of relationship was reported (1 month to 43 years), the median duration being 3 years. Of the 786 respondents reporting a steady partner over the past 12 months, for 24% this relationship was now finished. One third of relationships had begun within the year; at the time of the survey, 35% of those with a steady relationship lived with their partner. Relationships were described as exclusive in 51% of cases. Of the 83% who had been tested for HIV, 69% had last taken a test during the preceding 3 years.
The use of condoms during anal sex between steady partners appears to be closely linked to the duration of the relationship. On average, 57% of respondents used a condom during last anal intercourse; however, this frequency was 78% among couples together from 1 to 6 months, and decreased to 42% among those together more than 10 years.
Reported strategies for management of HIV risk within the couple
Respondents reporting a steady partner within the course of the previous year were presented with a number of scenarios describing possible strategies they may have adopted for managing HIV risk, both directly within the couple (irrespective of possible contact with casual partners), and within the couple subsequent to contact with casual partners. They were asked to report the strategy that best described their situation.
Abstention from anal sex with the steady partner was reported by 16% of the sample, either because they did not usually practice anal sex (14%) or as a result of the fear of HIV (2%). Consistent use of condoms with the steady partner was the most commonly reported way of managing HIV risk within the couple (43%). ‘Negotiated safety', in which both partners had taken an HIV test with a negative result and subsequently stopped using condoms, was reported by 25% of respondents. A minority reported that they had not taken the test together and did not use condoms, either on the basis of an assessment of past risks (6%}) or because they were faithful (4%). A few couples, in which both members were HIV positive, did not use condoms (1%). Other, unspecified, ways of risk management were reported by 5% of respondents.
Three-quarters of respondents had talked with their steady partner about ways of managing HIV risk with possible casual partners. The most frequently mentioned outcome of the discussion (58%) was a decision to maintain prevention, either by abstaining from anal sex or by always using condoms with these partners. However, some had discussed it only vaguely (10%), had taken no decision (7%), or reported using some other unspecified approach (3%). The reasons mentioned by the 24% of respondents who had not discussed this topic with their steady partner, mostly made reference to an assumed absence of risk, either because the respondent did not himself take any risk with casual partners and assumed his partner was doing the same (47%), or because of an alleged absence of casual partners (18%).
Those reporting a steady partner in the course of the previous year represent a heterogeneous group in terms of ‘stability'. Describing the two extremes, this group will include not only individuals who have a long-lasting, exclusive steady relationship, but also those who in the year have experienced a short-term relationship and who have had several casual partners both before, during and after that relationship. In order to reduce the level of heterogeneity in this group, those respondents who both described their relationship as exclusive and who reported not having had any casual partners over the past year (n = 173, hereafter referred to as ‘with steady partner only') were compared with all other respondents reporting a steady partner in the course of the year (n = 598, hereafter referred to as ‘with both steady partner and casual partners').
The strategy of ‘negotiated safety’ was most popular with the group with a steady partner only; reported by 37%, compared with 21% for the group with both a steady and casual partners. In the case of the latter group, the strategy most frequently reported (49%) was that of regular condom use within the couple, the choice of only 27% of those with a steady partner only.
Sexual practices and prevention of HIV/AIDS in relation to the type of partner
A number of questions were asked regarding actual sexual practices over the past year with both the steady and with possible casual partners. Among respondents with a steady partner only, 24% reported abstaining from anal sex and 6% from oral sex (Table 2). Among those who reported these practices, 33% consistently used condoms for anal sex and 48% never had semen in the mouth. Among respondents with both a steady and casual partners, the proportion abstaining from anal and oral sex with the steady partner was the same as among respondents with a steady partner only; however, condom use with the steady partner was higher (57%) and 69% never had semen in the mouth. With casual partners, these respondents more frequently reported abstention (41% for anal sex and 12% for oral sex), condom use for anal sex (89%), and never semen in the mouth (89%).
Comparison of sexual practices with reported strategies
The sexual practices of respondents were compared with the strategies for HIV prevention that they reported having adopted. As described in Table 3, overall, practices with the steady partner as reported by respondents were very consistent with their claimed ways of managing HIV risk. The prevalence of the avoidance of practices at risk or of consistent condom use was high and indicates a good level of protection. However, the comparison of strategies with actual practices reveals a number of situations that leave some respondents open to the possibility of HIV transmission. Therefore, it would appear that of those with both a steady and casual partners who have given up condoms on the basis of risk assessment without taking a test, 83% used condoms irregularly with their steady partner, and 10% used condoms irregularly with their casual partners. Irregular condom use was also relatively high (60% with steady; 23% with casual) for those in this group reporting a strategy of ‘other’ ways, i.e. a strategy the reliability of which it is not possible to ascertain.
Sexual practices and prevention of HIV/AIDS in relation to the serological status of both members of the couple
Regarding the serostatus of members of the couple, 56% stated that their partner was HIV negative, 7% that he was HIV positive, 23% that he had not taken an HIV test, and 14% did not know whether their partner had been tested or not. Altogether, both their own and their partner's HIV status were known by 52% of the respondents. Of the 79% of couples who practised anal sex, the respondent knew his own and his partner's serological status in 55% of cases (Table 4).
The serological status of the two members of the couple was reported as:
•Both members HIV negative: 42% of couples;
•Both members HIV positive: 2% of couples;
•Discordant couples, i.e. one partner HIV positive and the other either negative, not tested or with unknown serological status: 10% of couples;
•Serological status unknown, either because one or both of the partners had not been tested, or because the respondent did not know whether his partner had been tested (excluding the situations described above): 38% of couples.
•No response to the question of the partner's serostatus (regardless of the respondent's status): 8% of couples.
Considering together all couples who practised anal penetration, half of the couples always used condoms in their relationship. Among couples who practised oral sex, 64% never had semen in the mouth.
Sexual practices differed markedly according to the serological status of the couple (Table 4). Comparing couples exposed to an actual or potential risk (HIV status discordant or unknown) with those in which both members were HIV negative, abstention from anal sex was found to be higher (29 and 27 versus 14%) as was consistent condom use (85 and 61 versus 35%). The pattern was similar for protection by avoiding semen in the mouth, which was also found to be higher in risk situations (80 and 68 versus 54%). In terms of protection, couples in which no response was provided concerning the serostatus of the partner behaved in a similar way to those in whom one or both partners’ serostatuses were unknown. Because of the wide confidence intervals, no clear picture could be drawn for respondents in which both members of the couple were HIV positive.
Considering all 786 couples, 20% did not practise anal penetration, 39% always used condoms in their relationship, 23% were both HIV negative and did not always use condoms, 14% were exposed to a risk of primary infection (or eventually re-infection) because of discordant or potentially discordant serostatus, a further 1% were exposed to re-infection because both were HIV positive, and information was missing for 3%. Exposure to risk with the steady partner (15%) was thus twice that observed with casual partners (7%).
Determinants of consistent condom use in anal sex with the steady partner
The determinants of consistent condom use with the steady partner were investigated by backward stepwise logistic regression (Table 5). The predicted variable was consistent (`Always’ versus ‘Sometimes or never') use of condoms for anal sex with the steady partner during the last 12 months. The following explanatory variables were taken into account: sociodemographic characteristics, indicators relating to the social network of the respondent, his sexual behaviour and characteristics of the relationship. Variables found not to be significant in the univariate analyses (P > 0.1) were excluded from the final regression model, these being: drug use, the composition of the respondent's circle of friends, whether his homosexuality was known and recognized by his father, by his mother, age of first sexual relationship with a man, and age difference between the partners of a couple.
Logistic regression showed the following variables, in order of importance, to be significantly associated with the consistent use of condoms within couples: HIV serostatus (more consistent use with discordant or unknown serological status or when non-response regarding the partner); the duration of the relationship (more consistent use during the first 2 years and in particular the first 6 months); the existence of other sexual partners in the year of the stable partner (more consistent use of condoms in the case of existence or not knowing); sexual behaviour (more consistent use when irregular with periods of intense activity); frequenting saunas and gay events (more consistent use in frequent attenders); and education (less consistent use for those without school-leaving certificate).
Limitations of the study
The difficulty of recruiting sufficient numbers of men with homosexual practices through representative general population surveys, has meant that convenience sampling of the kind adopted in this study has become standard practice in many countries. Previous Swiss studies [18–21], as well as studies carried out in eight different European countries  have yielded samples that are very similar in structure to the present one. The differences and similarities between random and convenience samples in homosexual populations have been described elsewhere [27,28]. One comparison has indicated that respondents in convenience samples tend to be older . This may be because random samples include younger men who have not yet come out or adopted a homosexual identity . In view of the wide variety of definitions of homosexuality possible, Sandfort  pointed out the impossibility, whatever the methodology, of sampling the ‘true’ homosexual population; each approach taps a slightly different segment of the overall population.
The respondents were asked to give information about their partners, with the risk of error inherent in such a method. However, two other studies [30,31] demonstrated that results based on such information may be considered reasonably valid. Research also indicated that risk behaviour is more often reported in questionnaire than in interview studies . Given the absence of agreement in the literature about the definition of a steady relationship, the definition of ‘steady partner’ was left to the appreciation of the respondent. No limits were set on the duration of the relationship, neither was there any specified requirement regarding living together. This has probably increased the diversity of the ‘steady partner’ situation referred to in our analyses.
Being self-administered, the questionnaire had to be kept as simple as possible. This precluded asking complex questions about the sequences of events, such as whether discussions about the management of HIV risk had occurred before any sexual activity with the steady partner. Consequently, definitive causal sequences cannot be established.
Characteristics of the steady partnership
This research found that three-quarters of gay people in this 1997 Swiss sample were at some time engaged in a steady relationship during the 12 months preceding the survey. It parallels findings about the general wish of male homosexuals to have a steady, loving relationship and on the prevalence of stable relationships in this population [1–4,33]. Virtually all homosexuals are likely to enter a steady relationship during the course of their life. Our data also confirm that condom use with the steady partner is lower than with casual partners.
Most men in gay couples were able to identify a strategy of risk management that was consistent with reported sexual practices. Several characteristics of the steady partnership indicated a potential risk of exposure to HIV infection: discordance of serological status, non-exclusiveness, short duration, high frequency of sexual relations and of anal sex. However, as revealed in logistic regression, variables associated with consistent condom use with the steady partner pertain to many of these same characteristics, the most important being HIV serological status of the partners (lack of knowledge of status or discordance), a belief that the partner had had other sexual contacts in the past year, irregular episodes of high frequency of intercourse, and frequentation of saunas and gay events (a variable strongly associated with a reported high number of casual partners). These circumstances associated with greater condom use are relevant from the point of view of HIV prevention. The question of the duration of the relationship is more ambiguous. All things being equal, a decrease in condom use in association with the increasing length of the relationship is not justified in terms of HIV prevention; the explanation is more probably to be found in increased familiarity and intimacy between partners.
Issues pertaining to gay couples with casual partners
Altogether, 78% of respondents reporting a stable relationship during the previous year had also had other partners during this period. Steady relationships between male homosexuals frequently involve casual partners. That exclusiveness is neither a reality nor an ideal for many homosexuals has been widely attested , and that monogamy, when chosen, does not last has also been shown .
Many studies have shown that homosexuals do not practise anal sex with all their partners , that anal sex is less frequent with casual than with steady partners [1,35,36], that the type of relationship in which the homosexual is involved may even be the most important predictor of the type of sexual practice , and that emotional involvement with the steady partner may be associated with less use of protection . A high level of protection during casual relationships, in which emotional involvement is limited, has also been confirmed by several studies [25,37,38]. In situations in which there are casual partners, protection with the steady partner takes the form of condom use, not of abstention from oral or anal sex, whereas with casual partners, protection is provided through both abstention and increased condom use.
This existence or potential existence of casual partners presents a two-faceted problem to the members of the gay couple regarding HIV prevention: how to manage protection with these casual partners, and how to manage protection with the steady partner. A high level of preventive behaviour is achieved with casual partners; however, the situation appears less clear with the steady partner himself, with whom uncertainties abound. Some respondents (13%) simply do not know whether their steady partner has casual partners. Although the majority of couples discussed these issues and made a decision to use protection with casual partners, this was not always the case. Each partner may then make unverified assumptions about each other's not having other partners, thus avoiding a topic seen as threatening for the dyadic bond, or may avoid thinking about it at all. When the topic is discussed, safety is quite often adequately negotiated, but sometimes the discussion remains vague or a possibly unrealistic decision not to have casual partners is taken.
Issues pertaining to the HIV status of the members of the couple
The figure of 81% of homosexuals who know their own HIV status found in this study is similar to or higher than that elsewhere in Europe (ranging from 33% in the Netherlands to 79% in France [1,39]), and 79% in North America . Nevertheless, this leaves one-fifth of Swiss gay individuals who do not know their own serological status.
Gay couples in which both members know each other's serological status are still less common. Various studies have reported proportions of 15 and 31% for 1992 English data , and more recently of 61% and of 76%, with 55% reported in one study of young homosexual individuals aged 18–27 years . In line with other published estimates, the present study found only 52% of steady partners who knew each other's status. This figure reveals the magnitude of uncertainty within which decisions regarding prevention are taken.
In couples in which the HIV status is mutually known, this knowledge is a very important factor in explaining preventative behaviour, as has been shown elsewhere . In couples in which both partners were HIV negative, anal and oral sex are frequently practised and the use of protection is low. Discordant couples have less anal and oral sex and use more protection; this also seems to be the case when both members are HIV positive, although the small sample size for the latter prevents definitive conclusions. Uncertainty about each other's HIV status characterizes the remaining couples. Here, the practice of anal sex is somewhat less, and protection is increased in both anal and oral sex, but remains far from being systematic.
This research found that three-quarters of male homosexuals had at some time been engaged in a steady partnership during the 12 months preceding the 1997 Swiss survey. Several characteristics of gay steady relationships result in the increased potential risk of HIV infection: they are rarely exclusive, are of relatively short duration, and sexual activity – especially anal intercourse – is more frequent than with casual partners. These data affirm the centrality of the steady partnership in gay life and the importance of the management of HIV risk within the gay couple.
The study confirmed previous analyses indicating a high level of protection in Swiss homosexual populations compared with other European countries . Protective behaviour was consistent with the probability of exposure to risk, and designated risk management strategies were consistent with reported sexual practices with both the steady and with casual partners.
The most frequently reported means of managing risk within the gay couple, chosen by more than four couples out of 10, is the reliance on condoms for anal sex. ‘Negotiated safety’ was chosen by one quarter of the couples. A further 16% abstained from anal sex. Although it is clear that no strategy is totally risk free, these three options are rationally the safest choices, and concern a majority (84%) of couples. The maintenance of ‘negotiated safety’ relies, however, on a high level of communication between the partners. In the couple, the risk from possible casual partners may be either inadequately discussed or not discussed at all. On occasions in which risk is taken outside the couple, it is then difficult to acknowledge and deal with effectively. Nonetheless, abstention from anal and oral sex is more frequent with casual partners, and a higher level of consistent condom use is achieved.
A further problem is presented in couples who have not taken the test together and who do not use condoms (10%), because their evaluation of the presence of risk may be based on questionable assumptions. Another potential gap in prevention arises from the risk linked to uncertainty about the serological status of the members of the gay couple. The decision to stop using condoms is sometimes taken without proper HIV testing, and unprotected anal and oral sex occurs in couples in which the serological statuses are unknown. People counselling homosexuals, particularly during testing for HIV, should be aware of these difficulties.
More generally, this study suggests that the context of HIV prevention in gay couples is characterized by a tension between a concern for prevention leading to a rational appraisal of solutions to the problem of HIV risk and emotional involvement in a steady relationship, where uncertainty is a prominent feature. This tension is presumably a feature of the context of HIV risk management for all gay couples, at least to some extent. Some couples are able to talk about these issues, reduce uncertainty, take rational and adequate decisions about prevention, and thus achieve negotiated safety, whereas others seem less able to go through this process. An investigation into the differentiating characteristics and interaction processes of these two types of couples would further our understanding of the successful management of HIV risk in male homosexual couples.
1. Bochow M, Chiarotti F, Davies P. et al
. Sexual behaviour of gay and bisexual men in eight European countries. AIDS Care 1994, 6: 533 –549.
2. Risman BJ, Schwartz P. Sociological research on male and female homosexuality. Annu Rev Sociol 1988, 14: 125 –147.
3. McLean J, Boulton M, Brookes M. et al
. Regular partners and risky behaviour
:why do gay men have unprotected intercourse?
AIDS Care 1994, 6: 331 –341.
4. Davies PM, Hickson FCI, Weatherburn P, Hunt AJ. Sex, gay men and AIDS
. London: Falmer Press; 1993.
5. van Griensven GJ, de Vroome EM, Tielman RA, Goudsmit J, de Wolf F, van der Noordaa J, Coutinho RA. Effect of human immunodeficiency virus (HIV) antibody knowledge on high-risk sexual behavior with steady and nonsteady sexual partners among homosexual men. Am J Epidemiol 1989, 129: 596 –603.
6. Doll LS, Byers RH, Bolan G. et al
. Homosexual men who engage in high-risk sexual behavior. A multicenter comparison.
Sex Transm Dis 1991, 18: 170 –175.
7. Schmidt KW, Fouchard JR, Krasnik A, Zoffmann H, Jacobsen HL, Kreiner S. Sexual behaviour related to psycho-social factors in a population of Danish homosexual and bisexual men. Soc Sci Med 1992, 34: 1119 –1127.
8. Dannecker M. Homosexuelle Männer und AIDS
. Eine sexualwissenschaftliche Studie zu Sexualverhalten und Lebenstil
. Berlin und Köln: Schriftenreihe des Bundesministers für Jugend, Familie und Gesundheit, Bd. 252; 1990.
9. Bochow M. Datenwüsten und Deutungsarmut. zu Defiziten in der präventionsorientierten AIDS-Forschung am Beispiel der Zielgruppe homosexueller Männer.
Zeitschr Sexualforschung 1995, 8: 39 –48.
10. Kippax S, Crawford J, Davis M, Rodden P, Dowsett G. Sustaining safe sex
:a longitudinal study of a sample of homosexual men.
AIDS 1993, 7: 257 –263.
11. Kippax S, Noble J, Prestage G, Crawford JM, Campbell D, Baxter D, Cooper D. Sexual negotiation in the AIDS era: negotiated safety revisited. AIDS 1997, 11: 191 –197.
12. Davies PM. Safer sex maintenance among gay men: are we moving in the right direction [Editorial Comment]. AIDS 1993, 7: 279 –280.
13. Elford J, Bolding G, Maguire M, Sherr L. Sexual risk behaviour among gay men in a relationship. AIDS 1999, 13: 1407 –1411.
14. Bosga MB, de Wit JB, de Vroome EM, Houweling H, Schop W, Sandfort TG. Differences in perception of risk for HIV infection with steady and non-steady partners among homosexual men. AIDS Educ Prev 1995, 7: 103 –115.
15. Sacco WP, Rickman RL. AIDS-relevant condom use by gay and bisexual men: the role of person variables and the interpersonal situation. AIDS Educ Prev 1996, 8: 430 –443.
16. Dubois-Arber F, Jeannin A, Spencer B, et al
. Evaluation of the AIDS prevention strategy in Switzerland mandated by the Federal Office of Public Health. Fifth assessment report 1993–1995
. Lausanne: Institut Universitaire de Médecine Sociale et Préventive; 1997. (Cahiers de recherches et de documentation, no. 120b).
17. Dubois-Arber F, Masur JB, Hausser D. Evaluation of AIDS prevention among homosexual and bisexual men in Switzerland. Soc Sci Med 1993, 37: 1539 –1544.
18. Dubois-Arber F. Evaluation des campagnes de prévention contre le sida en Suisse: rapport de l'étude homosexuels, novembre 1987
. Lausanne: Institut Universitaire de Médecine Sociale et Préventive; 1988. (Cahiers de Recherches et de Documentation, no. 23.6).
19. Masur J-B, Dubois-Arber F. Les homosexuels: étude 1990
. Lausanne: Institut Universitaire de Médecine Sociale et Préventive; 1991. (Cahiers de Recherches et de Documentation, no. 52.8).
20. Gruet F, Dubois-Arber F. Les homosexuels: étude 1992
. Lausanne: Institut Universitaire de Médecine Sociale et Préventive; 1993. (Cahiers de Recherches et de Documentation, no. 82.8).
21. Moreau-Gruet F, Dubois-Arber F:Les hommes aimant d'autres hommes: étude 1994
. Lausanne: Institut universitaire de médecine sociale et préventive; 1995. (Cahiers de Recherches et de Documentation, no 120.5).
22. Dubois-Arber F, Jeannin A, Spencer B, et al
. Evaluation of the AIDS prevention strategy in Switzerland mandated by the Federal Office of Public Health: sixth synthesis report 1996–1998
. Lausanne: Institut Universitaire de Médecine Sociale et Préventive; 1999.
23. Moreau-Gruet F, Cochand P, Vannotti M, Dubois-Arber F. L'adaptation au risque VIH/sida chez les couples homosexuels: version abrégée
. Lausanne: Institut Universitaire de Médecine Sociale et Préventive; 1998. (Raisons de santé 13).
24. Schnell DJ, Higgins DL, Wilson RM, Goldbaum G, Cohn DL, Wolitski RJ. Men's disclosure of HIV test results to male primary sex partners. Am J Public Health 1992, 82: 1675 –1676.
25. Hoff CC, Coates TJ, Barrett DC, Collette L, Ekstrand M. Differences between gay men in primary relationships and single men
:implications for prevention.
AIDS Educ Prev 1996, 8: 546 –559.
27. Messiah A, Mouret-Fourme E. Sociodemographic characteristics and sexual behavior of bisexual men in France
:implications for HIV prevention. French National Survey on Sexual Behavior Group (ACSF).
Am J Public Health 1995, 85: 1543 –1546.
28. Sandfort TGM. Sampling male homosexuality.
In:Researching sexual behavior: methodological issues
. John Bancroft. Bloomington: Indiana University Press; 1997. pp. 261 –275. (The Kinsey Institute series, no. 5).
29. Messiah A, Mouret-Fourne E. Homosexuality, bisexuality: elements of sexual socio-biography.
In:Sexuality and the social sciences. A French survey on sexual behaviour
. Bozon M, Leridon H (editors). Aldershot, England: Dartmouth; 1996. pp. 177 –202.
30. Coates RA, Calzavara LM, Soskolne CL. et al
. Validity of sexual histories in a prospective study of male sexual contacts of men with AIDS or an AIDS-related condition. Am J Epidemiol 1988, 128: 719 –728.
31. Seage GR, Mayer KH, Horsburgh CRJ, Cai B, Lamb GA. Corroboration of sexual histories among male homosexual couples. Am J Epidemiol 1992, 135: 79 –84.
32. Siegel K, Krauss B, Karus D. Reporting recent sexual practices: gay men's disclosure of HIV risk questionnaire and interview. Arch Sexual Behav 1994, 23: 217 –230.
33. McWhirter D, Mattison A. The male couple: how relations develop
. Englewood Cliffs, NJ: Prentice-Hall; 1984.
34. Hunt AJ, Davies PM, Weatherburn P, Coxon AP, McManus TJ. Sexual partners, penetrative sexual partners and HIV risk. AIDS 1991, 5: 723 –728.
35. Coxon AP, Coxon NH, Weatherburn P, Hunt AJ, Hickson F, Davies PM, McManus TJ. Sex role separation in sexual diaries of homosexual men. AIDS 1993, 7: 877 –882.
36. Moreau-Gruet F, Dubois-Arber F. La prévention du sida chez les homosexuels en Suisse: adaptation au risque de sida selon le type de partenaire. Soz- Präventivmed 1995, 40: 1 –11.
37. McKusick L, Coates TJ, Morin SF, Pollack L, Hoff CC. Longitudinal predictors of reduction in unprotected anal intercourse among gay men in San Francisco: the AIDS Behavioral Research Project. Am J Public Health 1990, 80: 978 –983.
38. Weatherburn P, Hunt AJ, Davies PM, Coxon AP, McManus TJ. Condom use in a large cohort of homosexually active men in England and Wales. AIDS Care 1991, 3: 31 –41.
39. Dawson J, Fitzpatrick R, Hart G, Boulton M, McLean J, Brookes M. Access to HIV testing for homosexually active men. Eur J Public Health 1993, 3: 264 –268.
40. Centers for Disease Control and Prevention. HIV testing among population at risk for HIV infection
:nine states, November 1995–December 1996.
MMWR 1998, 47: 1086 –1091.
41. Dawson JM, Fitzpatrick RM, Reeves G, Boulton M, McLean J, Hart GJ, Brookes M. Awareness of sexual partners’ HIV status as an influence upon high-risk sexual behaviour among gay men. AIDS 1994, 8: 837 –841.
42. Hoff CC, Stall R, Paul J. et al
. Differences in sexual behavior among HIV discordant and concordant gay men in primary relationships. J Acquir Immune Defic Syndr 1997, 14: 72 –78.
43. Hays RB, Kegeles SM, Coates TJ. Unprotected sex and HIV risk taking among young gay men within boyfriend relationships. AIDS Educ Prev 1997, 9: 314 –329.