Sentence:  Sometimes the <WSD>alphas</WSD> and omegas are rare, sometimes they are only males, sometimes they have altered sex organs. 
Meaning of the word marked with <WSD> tags:  In omegaverse fan fiction, a person of a sexually-dominant (and sometimes secondary) gender/sex that is driven by biology, magic, or other means to bond with an omega, with males of this type often having canine-like genitalia.