Kim Kardashian has been largely in hiding since the June 15 birth of baby North West, but just because she hasn't been stirring up drama doesn't mean her family can't do it in her absence. (That's why there's so many of them, you guys.)

Case in point: Sister Kourtney is being sued by a dude who says he's actually the father of her 3-year-old son, Mason.

Model Michael Girgenti filed court papers earlier this week saying sparks flew after he and Kourtney met during a 2008 photoshoot. Several months later, in March of 2009, they hooked up during a period when she and longtime boyfriend Scott Disick were "on the outs."

Girgenti goes into very specific detail about the sort of sex they had, but suffice it to say it was the kind that produces babies. And since Mason was born nine months later, he's surmised the toddler must be his child, not Scott's.

Michael now wants DNA tests and, assuming they go the way he says they will, joint custody. A hearing is set for next month.

Meanwhile, Kourtney's attorney told TMZ, "This individual has been selling false and fabricated stories to the tabloids for years about Kourtney Kardashian and her son, Mason. Scott Disick is Mason’s father. We have not seen the reported court filing, but we are informed that this individual has been seeking to get paid to publish his ridiculous pleading. His claims are absurd and this is simply another shameful attempt to gain publicity and profit from fictional stories about my client."