PHP permissions problem

My commercial host is set up with the public root directory, "public_html", owned by user: userid, group: nobody. Directories I create within public_html are owned by user: userid, group: userid. As a result, PHP does not have permission to create files or write to files in public_html, but it does within its subdirectories. Is this a common setup? Are there security problems with changing the ownership of public_html to user: userid, group: userid so PHP can create files within the root directory? Advice, opinions, and links to relevant information are requested. PHP 4.3.2/Linux/Apache 1.3.28 -- Lowell Allen