>>46286275Not really. Latias, Heatran, Thundurus etc. have genders and yet can't breed. Magnemite, Shedinja, Cryogonal etc. are genderless but can breed. Being genderless and being in the No Eggs group are different things.
I believe that the real reason most legendaries are shown as genderless is because they're rare, so people in-universe haven't studied them enough to determine their genders.