That was a mistake from the official translations. Looking at the raw Ch 5, that exact speech bubble of Baekwoo's mom contains the characters "알파" which literally translates to "Alpha" so that statement should be referring to herself as an "Alpha".
Also in Ch 7, Baekwoo was affected by his mom's pheromones and then next thing we see, the mother panicking that Baekwoo can feel her pheromones. Baekwoo even said that he can detect pheromones from other "alphas" too.
Therefore, Baekwoo's parents are: Omega Dad x Alpha Mom
Oo okok thanks ...i recently started reading and it confused me
His mom is an Alpha.
Wait is the mc's mom and dad both omega?