Actually it depends on the type of omegaverse. there are some which are controlled by destiny like soulmates. there are some that if you are bitten by an alpha no one can get you pregnant except the said alpha. there are some whch a beta and omega can have a child or beta to alpha but there are some that beta can only impregnate beta. there are some alpha x alpha and some omega x omega. it depends on the verse.
female alpha are the only one that more or so a hemaphrodites
in this anthology's omegaverse, afaik, only omegas can get pregnant (according to the explanation in the beginning of the book). Kudou too, often explains that male beta can't get pregnant. Miyauchi's smile in the last chapter is such an open ending, making people speculate whether he's pregnant or not. I guess we'll find out more in extra chapter when vol.3 comes out.
In the Omegaverse Project anthology anyone can get pregnant. Which is why Kudo was worried he might get pregnant when he was raped, and later on (SPOILER ALERT...
he offered to bear the child if Miyauchi couldn't. Miyauchi's inability to get pregnant (at the moment) has to do more with the childhood abuse he suffered, though the fact that he's a beta made it harder for him to get pregnant as opposed to an omega. See here: http://imgbox.com/xQKvabzq
So in recent ~answer~ chapter Miyauchi ate a lot more than before then Kudou ask for how many people he eats and Miyauchi just smiled. Is he pregnant or what? Male beta cannot get pregnant right? I am confused af