Hello and thanks in advance for any assistance anyone can offer

The short version of my question is.. How & when do exported variables get inherited into a newly created child process?

The longer question is... I assuming a program read into memory by the exec() system call to create a child process.... reads the ~/.bashrc and /etc/bash.bashrc login scripts... And loads the environment variables from them... But how does a parent process pass an exported variable to the child process?

I'm trying to make sure I understand the exact sequence this happens in... Thanks for any help anyone can give me!