Tyga: I'd Never Smoke Weed Around My Kid

Sources close to Tyga say he would never put his son King Cairo in danger and that includes leaving him in the vicinity of marijuana ... when it's lit.

Kylie's BF posted a vid this week of his 3-year-old playing near a bag of what appears to be marijuana on a table.

Our sources say Tyga was totally shocked when people called him out for questionable parenting, because he didn't even know it was there. Tyga is adamant he's a responsible dad, pointing out there were a lot of people in the room, including Tyga's mom, and he has a strict "no blazing" rule around King.

We're told Tyga says he would never do drugs around his kid -- or allow anyone else, for that matter -- and there's plenty of hard proof he's daddy of the year. Like King's recent birthday.