Let’s talk about parenthood.
Is parenthood a biological concept?
Well… yes and no.
There’s biological parentage, but parenthood as we understand it is a sociological construct (and a complicated and fuzzy one that varies from culture to culture and family to family!). It springs from biological parenthood, but it isn’t biological parenthood. Most peoples parents are the individuals who directly contributed genetic material towards their conception, but by and large it’s the social ties we care about when we say that someone is our parent. Our society is ordered so that the social ties usually match the genetic ties, but there isn’t a 1-for-1 correspondence between them.
Imagine there’s a child whose biological parents are, for whatever reason, not around. This child is raised by her mother’s sister. Biologically speaking (but according to social labels that biology doesn’t even care about!) this woman is her aunt. However, on mother’s day, she gives her biological aunt a card and says “You’re the best mother I could have ever hoped for.”
Now imagine somebody acquainted with the bare genealogical facts of the case overheard this and jumped in to object all Ace Attorney style… but, you know, rantier. “OBJECTION! THIS IS COMPLETELY DELUSIONAL! HOW CAN YOU IGNORE BIOLOGICAL REALITY? THIS WOMAN DIDN’T CARRY YOU OR GIVE BIRTH TO YOU! MOTHERHOOD MATTERS! GENES MATTER! WORDS MEAN THINGS!”
See how awful that is? I think most of us would understand that this kind of conduct is 1) awful, 2) unnecessary, and 3) pedantic in the worst way, which means it’s 4) not even correct. The point that by a certain strict definition of motherhood that’s rooted solely in a narrow view of biology there is no mother/daughter relationship doesn’t apply EXCEPT within that same narrow framework, right? It doesn’t come to bear on who gets a mother’s day card.
So now imagine there’s no biological relationship between the woman who raised the child and the child, but everything else remains the same.
The objection is still awful, right? Still completely out of bounds, completely unnecessary, completely irrelevant.
Now imagine that the woman who raised the child not only didn’t bear this child but couldn’t bear children.
…it’s still awful, right?
I’m not imagining things when I say that. It’s still completely awful in the same ways.
"Mother" is a social role. It’s a role within society, but it’s also an interpersonal role (i.e., it describes a relationship between specific people), and it’s also an identity. It’s all of these things. There are also related biological concepts, but we don’t have to be talking about biology to talk about mothers.
And while the mother and daughter would swear they are each other’s mother and daughter and wouldn’t let anyone tell them otherwise, they aren’t going to literally ignore biological reality… that is, they won’t insist that they have each other’s DNA or pretend that the daughter has inherited risk factors or other genetic traits from the mother, if that comes up. It probably sounds silly that I’m even stipulating this, since… why would they?
Okay, so, now…
Let’s talk about womanhood.
Are there biological concepts related to womanhood? Sure. Did the concept of womanhood spring from biology? Broadly, yes. Do we as a society often wrap up the social concept of womanhood and the related biological concepts as if they were entirely one and the same? Yes, that does happen.
When a trans woman says she’s a woman… when we say we’re truly female, and therefore our bodies are women’s bodies…
We aren’t “ignoring biological reality”.
Not in the sense that anti-trans activists mean it.
We’re ignoring it in the sense that a mother who is not genetically related to her daughter is, which is the most neutral sense of the word “ignore”: not paying attention to it at the moment because it’s not relevant to the subject at hand.