"Adopted progeny" does in no way indicate that Kyrie and V are the same gender, there are different reasons why they don't have kids of their own
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a) One of them is simply sterile, happens all the time with humans too
b) A close friend/relative to them died and they took in their children
c) All elves are born by a single elf-queen, and then distributed to the other elves to raise them.
d) Elves actually have three sexes, and need the third one too to make kids. But they haven't found the right one yet, so instead adopted the children
e) Maybe the female one simply didn't want to go through the pains of birth
f) V and Kyrie aren't really married yet, but believe in "no sex before marriage", which makes getting kids of your own hard.
g) Uhm... ok i'm running out of reasons now :)