[Buddha-l] Men and women of good family

[Vicente Gonzalez]

What's the real meaning of "men or women of good family"?

I cannot find nothing about this.

This appears both in Pali and Mahayana literature, and I wonder
if it must be understood as a reference for the economic or moral or
social, etc.. 
I wonder how this use was able to travel among different countries
across times without special variations.

Why existed a general acceptance of this formula in all Asiatic
countries?.
It was understood as a kammic requisite for the way or it was only
a protocol use to talk about anyone engaged in the Buddha way?