'Big Brother' Aaryn -- TOOK A BLACK GUY TO PROM ... Says Mom

"Big Brother" villain Aaryn Gries CAN'T be the homophobic racist she appears to be ... because she took a black guy to her high school prom, this according to Aaryn's mom.

We're still waiting for the photographic evidence ... but Aaryn's mom reached out to the L.A. Times and insisted it's true.

There's more ... Aaryn's mom also says the reality star once dated a "Cuban American."

Still more ... Aaryn's mom says the reality star recently sponsored a Filipino child through a charity and "she has cousins of Japanese descent who she truly loves."

Despite all of that ... Aaryn's mom says, "While I love and continue to support my daughter Aaryn, words cannot describe my disappointment in some of her comments made on 'Big Brother.'"

"These inappropriate comments certainly do not represent the value system under which her father and I have raised her."

As for gays, Elizabeth says Aaryn "has never discriminated against anyone for their sexual orientation whether within our family or not. Aaryn truly loves all people equally."