Does anyone know the kids genders (like omega , beta, alpha)

the twins are alphas but idk abt jae

joo*

Joohyuk is likely an alpha given the conception dream represented him as a dragon, which is just like in the conception dream at the beginning of the story for his alpha father. The dragon symbolism means he's likely got a fated omega out there whose mother had a conception dream about the omega as a pearl, just like the dream that was had about Joohyuk's "mother" Yeon from the beginning of the story.

Also, Joohyuk has the more typical build of an alpha, looking almost exactly like his father but with a palette swap. This doesn't necessarily mean anything, given Joohyun looks like his omega "mother" Yeon, but is apparently actually an alpha. But it checks out with pretty much every other alpha in the story.

Disclaimer: This is just my interpretation. It's never stated anywhere in the text.