Board Thread:Naruto: The Last Discussion/@comment-732150-20150205151208/@comment-25632268-20150205155342

Munchvtec wrote: it's simple really. hamura did some human girls and there kids got byakugan.

And yet when Naruto did Hyuuga girl their children are without it :D Yeah yeah, I know that Kishimoto somewhere said it was a mistake on his side.

Being serious - Hamura looks like last minute addition, so he and his story isn't really developed, so all we got is assumption that yeah, he impregnated at least one woman before going to the moon and that's it. Besides, even on the Moon he managed to repopulate to the point where there was a division in the clan (looks like it runs in his blood to make Main and Branch family) and both sides had a size of an army.