I remember when my nephew was born he had milk. Seems its common but disappears not long after birth. (Something my brother asked about like 10 years ago so I don't remember the details.)
So, with that I would say it would be impossible just knowing human biology and not having to make up "magical" reasons. I didn't study biology though so what I know could be incredibly misremembered. XD
Male mammals are all born with mammary glands, it's just that they don't produce the hormones to fully develop them.
But it's not impossible. For this universe it would depend on the author.
everything is possible in the world of omegaverse, I've read a Doushinji where the omega had to massage his chest to breastfeeding the baby later on, and then I read some other story where the baby drank milk formula. What I love about this universe is the fact that's so malleable to your imaginationc :D/
human males' breasts can and will lactate under certain circumstances, but why do you want to think about all that?
Original Poster was probably thinking of breast-feeding. I'd be more concerned about little beast teeth *owie*
Just curious....
Does male omega produce mammary glands?