Not true. In a lot of OO lanuguages in the child class you can choose to redefine (inherit) or override (no inheritance) or even in some languages, undefine the function.
E.g. in Eiffel (which probably has one of the best OO models going) to allow for real multiple inheritance you can choose to rename, redefine or undefine (or a few others iirc)
code example
PHP Code:
class
child
inherit
parent
redefine functionName
end
feature
functionName
do
precursor --run the function of the same name in the parent
--then do whatever
end
Similar functionality is available in Delphi.