Someone who was born male but believes they are female, identifies as female, appears as female, lives their life as a female etc
It is a demonstrably false claim to say that anyone other than a female can 'live as a female' .
The only true statement is that a person from one sex can live the life they perceive as being of the opposite sex. They are living out their perceptions and how they think that a person of the opposite sex lives life.
To make that statement believing that a male taking artificial hormones with a penis converted into a replica off vagina and that may be readily perceived as a woman by some, is just that. A male taking artificial hormones with a penis converted into a replica off vagina and that may be readily perceived as a woman by some people.
That does not mean they have any clue as to how a female, who has had a female sexed body since birth, lives their life. How having that body since birth has shaped the group of people that represent half of the population.
Considering how many of them transition after many years of living as a male, I have not yet been convinced by anyone that they should have the protections against negative sexist discrimination that females need from birth.
They need their own protections, but that is NOT feminists job to secure them.
And it does not matter how many of these males there are. At all. It is irrelevant. they are not females. Despite some feminists wishing to include those males in their work. And despite some organisations trying to make feminists the 'mothers' of the world to fight for other's rights ahead of their own.