"Man I think I need a girl to have about 8 kids for me," the 27-year-old tweeted.
The Keeping Up With the Kardashians star's comment perhaps isn't all that surprising. After all, he's often surrounded by sister Kim's daughter North West, 14 months, and Kourtney's son Mason, 4, and baby girl Penelope, 2. (Thanks to Kourtney, he also has a fourth niece or nephew on the way.)
Earlier this week, he gushed about his niece Nori via Twitter. "Goodness @KimKardashian she's soooooo pretty!!!!" he wrote, along with a picture of Kanye West's little girl. "LOVE HERR."
Kim replied: "@robkardashian she loves her uncle Robby!"
Last year, Rob told reporters he'd love to start a family—when the time is right. "You gotta be married first, that's my rule: marriage then baby!" he said while hosting CIROC Vodka NYE Countdown at STK in Miami, via Access Hollywood.
"I'm sure that will come down the road," he added. "I'm sure that's something in the future."
Rob briefly dated Rita Ora in 2012. Last month, his famous family defended him when ex Adrienne Bailon—whom he dated from 2007 to 2009—slammed him for cheating during an interview with Latina magazine.