Men who have sex with other men (MSM) are a vulnerable population in Africa that has been insufficiently explored. Given the high rate of bisexuality among MSM (73% in the past year), it is important to understand their risk-taking behaviors regarding both men and women.

Methodology/Principal Findings
A socio-behavioral survey was carried out in 2007 among 501 MSM recruited using the snowball sampling method. We explore in this article why a condom was not used during last sexual intercourse with a man and with a woman, taking into account the respondent's characteristics, type of relationship and the context of the sexual act. In the survey, 489 men reported that they had had sexual intercourse at least once with another man during the previous year, and 358 with a man and with a woman. The main risk factors for not using a condom at last sexual intercourse with another man were having sex in a public place (aOR = 6.26 [95%CI: 2.71–14.46]), non-participation in an MSM prevention program (aOR = 3.47 [95%CI: 2.12–5.69]), a 19 years old or younger partner (aOR = 2.6 [95%CI: 1.23–4.53]), being 24 years or younger (aOR = 2.07 [95%CI: 1.20–3.58]) or being 35 years or over (aOR = 3.08 [95%CI:1.11–8.53]) and being unemployed (aOR = 0.36 [95%CI: 0.10–1.25]). The last sexual intercourse with the respondent's wife was hardly ever protected (2%). With women, the other factors were a 15 years or younger partner (aOR = 6.45 [95%CI: 2.56–16.28]), being educated (primary: aOR = 0.45 [95%CI: 0.21–0.95], secondary or higher: aOR = 0.26 [95%CI: 0.11–0.62]), being a student (aOR = 2.20 [95%CI: 1.07–4.54]) or unemployed (aOR = 3.72 [95%CI: 1.31–10.61]) and having participated in a MSM prevention program (aOR = 0.57 [95%CI: 0.34–0.93]).

Conclusion
Having participated in a prevention program specifically targeting MSM constitutes a major prevention factor. However, these programs targeting MSM must address their heterosexual practices and the specific risks involved.