Men can not give birth. They do not have vaginas, a uterus, periods or lactating breasts.The term "birthing person" is demeaning, insulting and makes mothers invisible. Cis is an insulting term, as is TERF.

Not all mothers are birthing people (adopted mothers) and not all birthing people would be considered mothers (many who choose to give up their children for adoption or are surregates don't consider themselves a mother to the child they don't have.)

I'll actually give an example I heard of recently on why this can be harmful. There is a lesbian couple who had a baby with help from science. And people ask them who the "Real mother" is. They want to know who gave birth, but the question implies one doesn't fill the role of a mother, when both raise the child and are mothers. Meanwhile, that would be avoided if they asked who gave birth.

I agree is insulting and demeaning, but using accurate language to specify only the group you are referring to isn't doing that, because conversations about mothers and birthing people should be talking about different things (raising a child vs changes in the body after being pregnant. for example.) Meanwhile I often see these terms attacked and made fun of without actually understanding where and how they are used. Without bringing trans people up (as you notice, my example didn't include them in it for why it's more accurate), can you explain why it's demeaning, insulting, and makes mothers invisible when conversations about mothers and conversations about people giving birth are different conversations?

Also, I am cis. It's not an insulting term, but a scientific one. It just mean's "not trans", and only really is used when relevant.