It's a yaoi genre. Basically a hierarchy.
Alpha: At the top. The one that gives the sperm and that is supposed to reproduce by impregnating an Omega.. Also weak to Omega's smells. Can mark the Omega's by biting the. I believe marking someone makes them your partner.
Omega: 2nd best, The birth givers. Omits a smell when not taking medicine to suppress their hormone smells (makes Alphas go crazy for them). Can be marked by an alpha.
Beta: The lowest on the hierarchy. Can impregnate (i believe) but super hard for them to do so cuz they supposed to be the weakest.
But I have limited knowledge on this cuz I don't really read omegaverse yaois.
Read this: http://www.mangago.zone/read-manga/abarenbo_honey/
They explain it.
I think you have omega and beta mixed up
yep, practically what Circan say however I think its might be the other way around for Beta and Omegas.
From what I've known at the top is the Alpha because people who are born as Alpha are usually elites. Also they produces the highest pregnancy rate and bigger sex drive (erection last longer or ejaculate more times). Just because you're an Alpha doesn't necessarily mean you have to end up with an Omega. Alpha can marry other Alpha as well to have a higher chance of producing a child who is an alpha or Beta in some cases. However, they tend to lose themselves (can't control their actions) if they smell an Omega in heat.
The bite mark means that when an Alpha bites an Omega, the Omega is his. If the Omega have sex and it wasn't with the person who bites him than he'll get dizzy, nausea, even fainting and there's no solution to that. However it doesn't do anything to the Alpha (I know, not fair right). After being mark it lets the Alpha know when their Omega is in heat and the mark also allow Omega to suppress their heat from others.
Beta, as far as I've know are the normal people who don't have heat cycle or anything. They have normal pregnancy rate.
Lastly, Omega are look down upon and discriminated because Omega are consider at the bottom. The heat cycle is 7 days within the month where Omega produces strong pheromones smells (usually make Alpha lose control of themselves) and their low pregnancy rate becomes a lot higher. In some cases they become useless during their heat. They're practically very horny for 7 days so they either hid in their house so they don't get attack by Alphas or they're masturbrating/having sex to calm down. If an Omega could suppress their heat, they might be able to get a decent job tho. Also seems to have medicine that helps suppress their heat.
Overall, anybody could get pregnant in an Omegaverse. Im not fully sure how female body works in Omegaverse but two woman can also produces children and are also categorize as Alpha, Beta, or Omegas.
Also, since its a made up alternative universe, not everything is use or is alter in Omegaverse based stories.
For example, Sometimes there is no bite mark and in some cases even Beta can give birth. It really depends on what the Author wants to use.
okay first this genre was a fan fiction but recently have made appearance in some manga alpha are the strong and elite group of society they are attracted by the the smell of omega .omega can be mates with omega they also can get pregnant by mating with alpha when they are in heat they also can be pairs by biting their neck but unfortunately omega always treated as sex slave
Beta are more common they are 70% of society they can mate with each other and they usually work for alpha beta can't be pairs with omega but can be affected by omega smell
Hope this help you
What does omega, beta and alpha mean?