It isn’t true that all women have vaginas nor that the correct definition of who is a woman is having a vagina. Similarly, it is not true that all men are stronger than all women:
A student who said women have vaginas and that it ‘was a fact’ that men are physically stronger is being investigated by her university. Lisa Keogh, 29, who studies law at Abertay University in Dundee, is facing disciplinary action after classmates reported the ‘offensive’ and ‘discriminatory’ remarks to staff.
However, it’s a pretty damn good approximation of how the world is.
Vaginal atresia is a condition in which the vagina is abnormally closed or absent. The main causes can either be complete vaginal hypoplasia, or a vaginal obstruction, often caused by an imperforate hymen or, less commonly, a transverse vaginal septum.[failed verification] It results in uterovaginal outflow tract obstruction. This condition does not usually occur by itself within an individual, but coupled with other developmental disorders within the female. The disorders that are usually coupled with a female who has vaginal atresia are Rokitansky-Mayer- Küster-Hauser syndrome, Bardet-Biedl syndrome, or Fraser syndrome. One out of every 5,000 women have this abnormality.
The statement that all women have vaginas, or that the presence of a vagina is definitional for woman is not true. But in being correct 4,999 times out of five thousand it’s close enough to being true that we can use it as a useful definition.
As with, say, Newton’s Equations. They’re good enough to get a rocket to the Moon, they work for most uses that we’re likely to have here on Earth. They start to be inadequate if we want to stick a lander on Mercury of if we’re trying to figure out stuff about fission or fusion perhaps.
It simply isn’t true that we all need to start doing tensor or field equations in order to work out the direction to point the cannon in.
So too our descriptions of male and female. Good enough as a short hand is good enough. We can then go on to deal with the edge cases at the extremes of our definitions when we need to.
But then that’s sensible and also how we deal with everything else which is exactly why we’re not doing it here, isn’t it?