Yeah, there are flags and stuff but where the fuck is there gay sex in Warframe? It has been some time since I played it the last time, but I'm sure I would have remembered that.
There is only implied gay sex if you date a 1999 Hex member who is the same sex as your Drifter. Then every time you walk past them in the mall backroom base of operations, you'll get tons of colorful comments about going to pound town later. It's kind of amazing.
Well, mass effect had one so, I guess DE just went why the fuck not ? I still need to do the hex syndicate to seduce Eleanor because I love Nyx but I have the other ones to do before.