Last night I was watching Little Miss Marker with my three-year-old --- or at least as much of it as the kid could stand. (I Netflixed it on a whim.)
Anyway, the plot of the movie is that Shirley Temple, who looks about four, has been left by her father with bookie Adolphe Menjou as collateral on a bet. The father never comes back, and Menjou has to take care of Temple while he figures out what to do.
The first night he's got her, Menjou gives Temple one of his pajama shirts. Temple says matter-of-factly that she can't wear her underwear (which looks like a one-piece bathing suit, pretty much) to bed, and Menjou tells her matter-of-factly to take it off. Which she does, on-screen, with the shirt for a bit of cover.
Here's the thing that surprised me most --- you see her nipples when she's changing. The scene is shot as frankly as it would be today, if not more so. (Are four-year-old girls' nipples permissible in light family comedies today? I dunno.)
So yeah. We're really weird about kids these days.