>>103021865>>103022017>Fucking in 40k
Most humans on most planets fuck. The Imperium raises Guard regiments by forcing planets to "tithe" thousands of able-bodied people at a time. Got to replace those soldiers somehow. Depending on the planet/local culture they might be encouraged to raise up loyal soldiers for the Imperium's righteous armies, or they might be celibate/sterile and reproduce through cloning or tech-assisted parthenogenesis or something.
Guardsmen can and do fuck. There are a lot of mixed-gender Guard regiments, and it can take months or years of space travel to get from one warzone to the next. I assume there's some kind of birth control (even if it's just "abstinence or the Commissar shoots you") in place for active soldiers, since getting preggers could cut a campaign short.
Space Marines are mostly celibate except for the aforementioned Space Wolves, who are viewed as unsavory degenerates by their fellow Marines. Especially the Dark Angels, whose primarch was named after a gay poet. Not trying to imply anything there. Anyways, it's up in the air as to whether or not non-yiff Marines are even capable of boning or if their bits are withered/amputated/useless as a result of their extensive genetic/surgical/cyborg modification.
Chaos Marines can fuck. Corsairs probably fuck. Emporer's Children definitely fuck, but they burned out on regular fucking 8,000 years ago so now they are into some shit so weird you can't even begin to imagine it.
Craftworld Eldar can fuck but probably have to meditate for two days before and after and aren't allowed to enjoy it during.
Dark Eldar definitely fuck but it probably doesn't bear thinking about.