I prefer same-gender saunas and steam rooms for several reasons. I prefer to be nude and co-ed nudity is not really in vogue amongst at least my typical compatriot American cruisers. Also much like the locker room at my gym (where we have sauna, steam room, and whirlpool - all usually nude) I see the area as sort of a male bonding space, an excellent place for conversation and camaraderie amongst all types and generations. I regularly visit Korean and Russian spas both solo as well as with friends for similar reasons. I look forward to the experience as such an essential part of my vacations that even on land I typically make sure that the resort has a men's sauna at minimum.
Glad to see others in the thread with similar views, it seems!