Rob Gronkowski's parents managed to feed and raise five boys who all became collegiate athletes, four of which have made it to the NFL -- Chris, Dan, Rob and now the baby, Glenn, signed by the Buffalo Bills as undrafted free agent.

Obviously Rob has enjoyed the most NFL success, more than almost every active NFL tight end as well.

Rob appeared on the Late Late Show with James Corden on Thursday where he explained how the brothers kicked the daylights out of each other in "brawls every day." But the mayhem wasn't competely unreglated, Gronk explains, because his parents set forth these two rules: "No hitting in the face and no hitting in the gonads" he said.

Thanks to the latter rule there might be 12-16 more little Gronks running around and punching each other one day.

During another segment, Gronk, Liev Schreiber and Luke Wilson subjected Corden to some absue in a carnival-style game: