NFL's Rob Ryan -- My Son's a Model ... And He's Hot!!!

Soooo ... Rob Ryan's son is a male model. And he has abs.

For those unfamiliar, Rob is the defensive coordinator for the New Orleans Saints ... and he's the twin brother of Buffalo Bills head coach Rex Ryan.

The Ryan brothers aren't exactly known for having shredded physiques ... but in the case of Joe Ryan, sometimes the apple does fall far from the tree.

Joe recently moved to L.A. for modeling ... and his dad came to town to visit.

In fact, we ran into the two on their way into the Lakers game at the Staples Center ... but for some reason, we just didn't connect the dots.