I think you are on to something.
Personally I have always wondered why such a sexist religion would even want females to go on field service, then I came to theory: (1)That a woman knocking at your door is less intimidating than a man, so you are more likely to get an answer. (2)Women are generally better a communication than men, so it's easier to start up a conversation or keep one going. (3) They cannot (men- ms, elders)bear children.
Any other thinkers out there wana add there 2 cents?