system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: Why are many toilet seats designed with only three sides instead of four? What is the advantage to removing the frontmost face?
gpt
It's for sanitary reasons and no other. 

It makes it easier to wipe for both sexes and it gives and little more breathing room so your junk doesn't hit the seat. This is the same reason public toilets in the US are elongated and ones in your home are sometimes round or elongated.

Uniform Plumbing Code Section 409.2.2 requires an open front seat: "All water closet seats, except those within dwelling units or for private use, shall be of the open front type.

The IPC and UPC care about keeping people safe and systems functioning correctly. They don't care about how much you pee, or toilet seat strength, or anything else you can come up with. They care about keeping people safe and setting a standard for installation.