I feel like it doesn't really warrant a response, but the statement is true nonetheless.

How would you respond to the statement "Trans women are biologically male" ?

with an earnest instruction for the person in question to sunset their lifecycle at their earliest convenience

Would ask to provide separate definitions for woman, man, male and female. We can't jump to conclusions about someone's statement before seeing the whole picture of what is happening in his mind.

Maybe, and why does it matter?

There's a lot to gleen from why the person is asking the question. It's not a good faith question. They already have their answer. I wouldn't engage it other than to ask another question like "why do you ask?" or "why does it matter?"

shrug. I mean its true but so.

Let them compete in non sanctioned ways. But there is a definitive advantage to having naturally occurring heart destroying hormones.

I don't think mtf trans folk are trying to game the system by going through transition hell, but in serious situations a mtf person who grew up on test is likely going to win the fight all other things considered.

They are genetically.
How they feel/identify is their problem

"How would you respond..."

Why are you asking me this question?

Why did you bring this up?

I'm in dire circumstances and need decent employment or I will not escape poverty. Are you going to do anything to help me?

Why are you thinking about this?

Do you even know or have met anyone trans?

Who are you?