Homosexuality is a subject that hasn't been covered in vedic astrology that much. There is not much data or research to go through when judging homosexuality in a chart. But in modern era homosexuality is no longer a crime. Today westerners have legalized it while many forward thinking Indians have accepted that gay relationship isn't a crime.

      Mercury seems to be the catalyst who drives gay relationships. Of all the famous celebrities from LGBT Community most of them have Mercury with ascendant lord or seventh house lord which drives them towards homosexuality. Unfortunately there isn't much data to go on. There is only moon charts of famous celebrities from LGBT Community. But one pattern seems to be that Mercury is involved. 

     Mercury in vedic astrology is a prince. Mercury with Saturn are the two planets who are termed as eunuchs. Mercury is known as prince and just like a prince he likes to try out new things and is not afraid or bound by society norms. Saturn is also a eunuch but he is rigid and loves to follow society norms. Mercury on the other hand is chatty, expressive and more than likely to fall for same-sex relationship. 

     Venus and Rahu both share Mercury's beliefs of trying the forebidden and trying experiments which lead to sensual and sexual gratification. But both of them seem to be driven by showoff and both hate to look bad in public eye. Venus and Rahu may try gay relationships but both are unlikely to make a native come out of closet as they seek society approval. Mercury on the other hand is not that interested in approval from society or peers. 

     The circumstances for gay union are not really different from those of heterosexual couples. Jupiter or Rahu placement or aspect on house of marriage or a favorable vimshottari period is the driving factors to seek gay union.

     Ofcourse a few celebrity couples and horoscope are not enough to derive a pattern. Many horoscope charts and data from it need to be analyzed to get clear patterns and also get more information on those seeking gay union. If and when those are available a new article perhaps with much more clarity would be made available.