You can call XML a child of SGML, or a new iteration of it. One view
establishes a separation and the other eliminates it. Neither has any
particular basis in reality: they are both rhetorical views.
Consider:
C++ (as a random example) must also forge its own way in a different world
than previous iterations of it grew up in. Unlike XML, it wasn't renamed
as it was adapted for new environments and tasks. Nevertheless, it went
from being a Unix-centric front-end to C into a massive programming
language used on every platform with compilers that border on artificial
intelligence. Is modern C++ a "child" of that older one? Or is it just a
new version? Stroustrop once told me that if he were going to update the
ARM, he would essentially have to rewrite it from scratch. The differences
between C++ in 1986, 1990, 1993 and 1998 are much more severe than those
between "old SGML" and XML.
Paul Prescod - http://itrc.uwaterloo.ca/~papresco
"Perpetually obsolescing and thus losing all data and programs every 10
years (the current pattern) is no way to run an information economy or
a civilization." - Stewart Brand, founder of the Whole Earth Catalog
http://www.wired.com/news/news/culture/story/10124.html