Here’s an explanation from Wikipedia without being forced to watch an hour-long video.
Works in the Omegaverse genre typically depict characters as possessing two sexes: a primary sex (male or female) determined by their external sexual organs, and a secondary sex that manifests during puberty, determined by their internal reproductive system.
Between Alphas and Betas, only females can carry on a pregnancy, but male Omegas are often envisaged as being able to become pregnant via a uterus connected to the rectum, and Alphas can impregnate regardless of their main gender.
Here’s an explanation from Wikipedia without being forced to watch an hour-long video.
Link
So they’re intersex.
Thank you, informative internet stranger.
This is the weird shit I come to the internet to find out about.
That’s what I’m saying!! I was like “I bet this is weirder than I think” and I was right.
Bring on the weird!