It depends. The rules depend on the author but in some of them, anyone(even betas and alphas males) can give birth. But i think the omegaverse version where only omegas male and women can give birth is more popular.
Can you suggest a manhwa where a female alpha & omega had a baby?
Have you ever come across a beta getting impregnated? If so can you link it?
http://www.mangago.zone/read-manga/okusama_ha_alpha/
Here is alpha getting pregnant.
http://www.mangago.zone/read-manga/kashikomarimashita_destiny/
2nd couple, beta gets pregnant
Thank You
Thank you
Correct me if I'm wrong but when it comes to the Omegaverse isn't that putting everyone on the same playing field? Like it doesn't matter who you date because you'll still be able to conceive a child with whomever? (If I'm explaining that right).