Custom Widget areas in Child Theme Problem

I’m Currently trying to add custom widget areas into the child theme, it was my understanding i just had to recreate the same file in the child theme with the same directory path/location.

I did that and this is the error i’m getting.

Fatal error: Cannot redeclare browser_body_class() (previously declared in /home/content/57/8705157/html/ces/wp-content/themes/blogs-mu-child/functions.php:79) in /home/content/57/8705157/html/ces/wp-content/themes/blogs-mu/functions.php on line 91′

It appears it is still reading the child and parent functions php at the same time. Any help would be much appreciated.