Nothing against homosexual romances or homosexual people, but if you are creating an ark to ensure the survival of certain species just relocating and finding a new home is not enough as you have to ensure the specimens you take are able to procreate and re-populate the species and until the feminist overlords eliminate the need for males by perfecting the science of creating sperm cells from a female donor's stem cells (something that still has not been achieved in the Mass Effect universe due to the infestation of males that seem to worm their way into the setting) homosexual relationships just aren't a viable means for reproduction.
Is this a theme that will ever be explored in the new setting? Perhaps even by including homosexual romances and exploring a theme where the player has to choose between being with somebody they love and sacrificing that love for the good of the colony, with every new frontier new challenges are faced but does the good of the colony come before those you love?
Hmm. I don't think this opening post is homophobic.
However I feel that it this space is going to be invaded with bigots.
Fingers crossed it doesn't...
Now to answer your question. I don't think it is at all selfish.
The reason people ask for more and better representation for minority groups is because there is a lack of it.
I doubt that people think of an ultra camp supremely effervescent personality for gays and ultra butch personality for lesbians. I think enough homosexuals are out of the closet to bust that myth.
That said, if your only experience of LGBT's is through fiction, you're left with a handful of representations and they're normally hyper stereotyped. So I don't think it's "selfish" to expect homosexuals in the setting.
Regarding reproduction: homosexuals never had a problem with reproduction. Copulation is not the only means to reproduce. This has been possible before test tube babies, cloning, augmented humans etc. So here is the key. Human sperm to fertilise woman. The woman gives birth nine months down the line. Done. It's not really that complicated. If 100% of humanity were homosexual the species would not become extinct. We'd merely adapt.