Do we even need to segregate bathrooms by gender anymore?
These days people are more private than they were when your grandfather was young. I can’t speak for women, but I’ve been in plenty of men’s restrooms. Lots of closed off stalls and every urinal is sectioned off with a divider. If a woman walked in, they wouldn’t see much in terms of the privates. I’ll wager that most women’s restrooms are the same these days. Nothing to see, move on.
Why not just make all restrooms unisex?
It would be more efficient. You would avoid the situation where there’s a long line to use the women’s restroom but nobody in the men’s restroom (and vice versa). Since you’re combining the space of two restrooms together, the restrooms would be a lot bigger and use space more efficiently (instead of two sets of two hand dryers, maybe you can get away with one row of three).
Gender wouldn’t matter anymore. It is obvious. No more logistical problems involved with a mom taking her little boys to potty. No more closing of the entire women’s restroom for cleaning just because the janitor is a man. No more hard choices, courage, or awkwardness required for transgender people to choose a restroom.
What about security? It shouldn’t be much of a problem, but there would be some rare edge cases. After all, an empty restroom at night is the equivalent of a dark alley. It’s likely a risk whether the restrooms are segregated or not. But if restrooms were made unisex, they would in a way become more public and less like a dark alley. People would be more likely to walk in or check on suspicious activity.
There is a scene in the 1997 film Starship Troopers where men and women play full-contact sports together and shower in the same locker room afterward. It’s not awkward at all. Is this how the future will be? Maybe.