By the 23rd century words such as 'gay' or 'straight' would be obsolete. People would just be people with lovers/partners/mates/spouses, regardless of sex or orientation.
As for crew gossiping, the fact the CO and XO were in a relationship would be something more shocking and cause for concern (due to conflict of interest), rather than them both being the same gender.
I don't see why some people have to make writing a same sex relationship such an important thing, its just the same as a heterosexual one except both parties involved have the same equipment. The emotions involved and intensity created are just the same between man/man or woman/woman as it is with man/woman. I have no problems developing an emotional and physical relationship between my male and female characters, so I don't see why other authors have to make such a big thing about it for homosexual ones.
Just my thoughts.