You know .... there is another angle here. To them, the "affect" may not be so dramatic. Just as you often hear caucasians say that they can't tell how old Asians folks are. It is because we are not used to their looks. We think they look so perfect because they are essentially "new" to us. Yes, they do have smoother faces etc... but to them the differences are probably not so "passable". Consider this: can you tell a Chinnese person from a Thai or Cambodian ?? It is easy for folks from there, while nearly impossible for the average American.
I think it is a little easier for them to pass, but not as much as we think -- from our perspective. As well, many of the lady boys start quite early. Given that same spring board, we would look very passable too.
