@Abiday9 There two are the only one that have an obvious secondary gender since birth, and in the case of fe.ale Alphas is not always 100% obvious until puberty. The other secondary genders are not obvious and do have "presentations" at puberty.
@Abiday9 In my version of ABO verse , male Omegas have a sort of vagina (a vaginal opening between the dick and ass) a dick (no scrotum) since birth , while female Alphas have a normal vagina (labia, urinary opening etc.) and the clit developes into a penis.