Being based roughly on medieval society, we can generally suppose that Vosca mirrors the medieval period in an overall practical approach to sexuality.
Birth control is virtually nonexistent in Vosca, beyond the basic methods available to them technologically. The Genosians consider parenthood a sacrament, and have a Gilgamesh-esque schema where those who do not have children basically have their afterlives "capped" at a certain quality. Albeit, not a terrible one, but still not as swanky as the guy with eight kids.
In Genosian society, as so much emphasis is placed on fertility and the raising of children, homosexuality has negative connotations. This is not due to any inherent immorality of the act, but because children cannot be produced. Gay men who are exceptionally hard workers or who marry and have children but keep up their activities are accepted by society. As with many historical cultures, it appears to only count as adultery if it's with another man's wife.
Lesbians are ignored, mostly. Women usually end up married whether or not they want to, but what they do with women after that is irrelevant to most of society. It has been stated many husbands are okay with this, most likely because lesbians probably aren't going to cheat on you with another man.
Dessian society cares much less about homosexuality, as adoption is more accepted and blood relation matters less in a meritocratic caste environment.
Zells do not particularly get the idea of sex for pleasure, and so homosexuality doesn't really occur in their species.
Ohanedin don't care, as long as you are faithful to your partner. Fidelity is an extremely important business to Ohanedin.
Orredin have long since stopped caring about the other person's gender.