Summary
Representative Sarah McBride, the first out trans congresswoman, criticized Donald Trump’s executive order defining gender as strictly male or female.
McBride points out that biologically all embryos develop as female until the SRY gene activates weeks after conception.
The order, which ties gender to reproductive cells at conception, unintentionally categorizes all humans as female from conception based on biological facts.
McBride’s remarks highlight scientific flaws in the policy.
As far as I know, intersex is caused most often by a double fertilized egg, or that thing that happens when one twin absorbs the other in utero, chimeraism or mosaic. Something similar causes Down syndrome, an extra chromosome gets in there somehow.