Hitchcock liked to explore sexuality in films such as ROPE, STRANGERS ON A TRAIN and others, as much as censors would allow. No judgement, no preaching, just part of humanity. I watched SUSPICION the other night and there's a scene at a dinner party at the mystery writer's house and one of the guests is a blonde lady with very short hair wearing a man's suit and tie. No deal is made out it, which is nice, and I thought maybe she was the mystery writer's girlfriend because, at one point, she gets up and pours a drink for the hostess as everyone is discussing ways to poison someone that can't be traced. The bird "expert" in THE BIRDS wears a man's suit and tie, too.
He could use sexuality for humor too. The newlywed couple in Rear Window are mostly unseen but it's pretty clear they're holed up in their bedroom non-stop. Any time the poor guy tries to take a breather at the window, she calls him back with that plaintive wail. It's surprisingly explicit without being really explicit at all. It's a clever way to "go there" in a family film. The train-in-the-tunnel ending of North By Northwest is actually laugh out loud funny, since even casual moviegoers would recognize the significance of such a well-used cliché coming on the heels of the two stars climbing into bed. In Rope there's a lot of giddy wink-wink between the two men as they savor the irony of being so charming to their guests after having murdered a previous guest, but it's a creepy humor that makes the movie audience feel complicit, which seems to have been Hitchcock's whole approach to the film.