For some reason, finding out Kim Kardashian is with child has caused millions of people to watch her banging Ray-J, like, a million years ago. People are weird.

TMZ spoke to the folks at Vivid Entertaintment -- which owns 'Kim K. Superstar' -- and discovered lots of Kim's fans are celebrating the baby with umm ... visual aids.

Vivid says video-on-demand purchases of the sex tape have spiked 80% since Sunday night ... the fattest increase they've seen since Kim's wedding to Kris Humphries.

Further, Kanye's been boosting biz for months now. We're told overall sales of Kim's sex tape -- be it VOD, online, or DVD -- have steadily increased every month since he and Kim hooked up last Spring.

It’s pretty much inevitable a “leaked” contraception video is going to pop up in the coming months so enjoy the internet while it’s still standing.

[H/T: TMZ]