Is there a reason why a woman cannot be priest

They can.

It would disrupt the gay order of things.

Because it's a man's religion.

the vagina gives easy entrance for possession

I haven't read enough into it (there's always more to read into), but i believe it is because God is the head of the man, and the man is the head of the woman, or something like that. It's in order to show respect to God by showing him that we accept the way he has created man and woman.

There are female priests in the Anglican Church.

Nov. 2/16
2:31 pm

Priestess

From the start priest are only man.
So woman cant b priest because he is not a man.