This makes sense - by "reflect the sex they are claiming to be" do you just mean they are suitably feminine and appear to be a woman?

This is a fairly reasonable take, or at least I completely understand why someone who is a straight man would not want to date someone who appears male, for example.

I guess one question I have is whether a female penis would be a problem for you as a straight man? Separately is having a vagina an important requirement for you to date a trans woman (you might be happy with a female penis, but still want penetration with a vagina, which is why I see these as two separate questions).