Characters
Sam, let me look at you... Fred, she's gotten her boobies!
— Grandmother · Sixteen Candles

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker demands a closer look at Sam, then announces to Fred, with crude delight, that she has developed physically. The remark ignores tact and privacy, turning a greeting into an embarrassing public comment on her body. The bluntness is the joke.
Context reviewed