system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If something happens to cause everyone in the world to be infertile, theoretically how long would it take us to find out?

I was just watching the movie Children of Men, great movie by the way, but I was just wondering what are some logical reasons that could cause infertility of the entire human race, and how fast we would be able to realize it.
gpt
1 week, rounding up to the nearest week. 

All the OBGYN's would suddenly have no one coming in reporting a pregnancy. They would each probably consider it just a fluke but after talking to other doctors they would realize something was off.