The daughter of NY Jets great Mark Gastineau is coming out swinging at the NFL -- saying the league has "major f***ing problems" when it comes to brain injuries like CTE.
Of course, Mark recently revealed he's been diagnosed with dementia, alzheimer's and parkinson's ... and suggests it was caused by blows to the head he sustained during his football career.
So, when we saw his reality star daughter Brittny Gastineau leaving Catch in West Hollywood -- we asked her what the league should do to tackle the issue ... and that's when she lashed out.