How did the term "coed" come to be associated with porn? And why does such a term continue to be used, when it really makes no sense?

Young Horny Coed Engaging In Extremely Wild Fuckfest!
Coed Teen Absolutely Naked In Her Bed Waiting For Someone To Play!
Cute Horny Busty Blonde Coed Getting Slammed On The Massage Table!

The term “coed” is a shorted form of the adjective “coeducational.” Often used as a noun, a “coed” describes a person (or, according to dictionary.com, only a female?) who attends a coeducational college or university.

First of all, the vast majority of colleges and universities are coeducational, and so I’m not sure why such a distinction even needs to be used. Shouldn’t “college girl” be sufficient? (Furthermore, wouldn’t a non-coed girl be even more appealing to people into porn? You know you love those chicks at all-girls schools getting down and dirty with each other…)

I just don’t understand the usage of this word in pornographic descriptions. What is the purpose of this specific distinction?