“Woman-born-woman” is such a ridiculous term, even by the biological essentialism standards of TERFs and other trans-antagonists. No baby is born with visible breasts. No baby is born menstruating. No baby is born with noticeable facial or body hair, or a higher or lower voice compared with average babies of the “opposite” sex. These largely secondary sex characteristics — which form much of the basis for harassment of women — all develop at puberty, and have a lot of variation even amongst cisgender people.
As for primary sex characteristics, the difference between the size of a penis and a clitoris at birth is a matter of millimeters. What kind of disgusting person cares so much about the genitals of an infant anyway? And at least in the U.S. at this time, babies (and adults) do not routinely undergo genetic testing; sex chromosomes for the vast majority of people are presumed, and entirely irrelevant to gender presentation in any case.
I’ve said it before and I’ll say it again: “Biological sex” is bullshit.