Gene Simmons' Son My Dad Can Be An Asshole ... But He's No Weinstein

12/22/2017 6:31 AM PST

Gene Simmons' Son Nick Defends His Dad After Sexual Assault Lawsuit

EXCLUSIVE

Gene Simmons' oldest son is coming to his dad's defense -- sort of -- calling him a cheater, egomaniac and sometimes abrasive ... but saying he's absolutely not a sexual abuser.

Nick Simmons was in WeHo Thursday and sounded off on the sexual assault lawsuit filed against the KISS rocker last week.

TMZ broke the story ... a woman -- who identified herself as Jane Doe -- sued Gene last week claiming during an interview in November he forcibly placed her hand on his knee, touched her neck and grabbed her ass.

Nick admits his dad has a reputation as somewhat of an asshole ... but assures us, he would NEVER do something to a woman against her will.