Homosexuality is a global human phenomenon that can either describe the behaviour, preference or identity in relation to sexuality with someone from the same sex. Although homosexuality is becoming more and more accepted in many countries of the world, in large parts of society it is still considered as deviant, unnatural and to be discouraged. A considerable proportion of countries in Africa, the Caribbean and the Middle East have some form of criminal laws against homosexual behaviour. Criminalisation of and atrocities towards homosexuals seriously hinders access to health care and endanger not only minority groups, but in the long run the population at large. The American Psychiatric Association removed homosexuality from its list of disorders over 35 years ago, yet homophobia among physicians is still widely prevalent. From a historical point of few, men who have Sex with Men (MSM) form a relatively new epidemiological risk group for STI. Yet it was the deadly HIV/AIDS epidemic that ignited a strong gay activist movement in the United States and Europe fighting for more research to find a cure and diminish disease transmission among MSM. Phylogenetic techniques and subsequent cluster analysis of STI pathogens have recently opened the possibility to unravel STI transmission networks in more detail and increased the insight into transmission mechanisms in MSM. To perform correct management, clinicians evaluating men with male-male sex contacts for STI-related complaints or STI screening must obtain a thorough sexual history. Emerging STI like lymphogranuloma venereum, hepatitis C and multidrug resistant Neisseria gonorrhoeae strains have been described first in MSM. STI-related proctitis often occur in MSM. Within the MSM population, HIV positive patients form a special group affected by STI-related diseases like anal carcinoma and neurosyphilis. The final part of this talk concludes with recommendations to reduce the STI burden in MSM.