X-Files

X-Files was an unusual series focusing on aliens and supernatural involvement in the world today, along with government conspiracy to cover them up.

'Gender Bender'in Season 1, has an appropriate title. In it, a killer who is able to swap genders and seduce at the touch kills numerous sexual partners. The swap happens during or just after sex, so the heterosexual partners would find themselves with a same-sexed partner

Season 7's 'X-Cops' is the first gay male horror TV show that I'm aware of. A black gay male couple is a major part of this show. Somewhat stereotypical representation, but realistic.