Yes, I was thinking the same, but I just couldn't face the amount of vile prejudice and bullying one is likely to encounter from a large tranche on the main relationships board. And perhaps it wasn't worth posting, usually I just make my observations myself! But it is about both sex and relationships, I think. Because what I have found is that, maybe weirdly (and perhaps this is at the heart of my question), when I've had a sexual relationship with a 20-something guy, it has grown out of an emotional connection that was just infused with the attraction somehow. But then, of course, it's not a viable 'public' relationship, because there would be so much condemnation of it.
However, as you say, flip it and a 40+ guy with a 20+ woman is aok.
I've noticed that the woman is always, though, seen to be 'lucky'. If, let's say (for labelling's sake) a 'mum' is with a 20-something guy, she's seen as somehow having something she shouldn't, and being damn lucky but at the same time unnatural and pretty much depraved.
If a 40+ guy is with a 20+ woman, again she's seen as lucky. For being, sensibly and quite acceptably, with a guy chosen for status and money, rather than being with a hot 20-something who hasn't made his money yet, presumably then just because he's hot. She's seen as having chosen wisely and reaping the approved benefits of protection, etc, and she's also 'sacrificing' her youth and beauty to slake the palate of a guy old enough to be her dad/grandad. (Which, personally, I find rather unsavoury)
The second scenario reinforces and supports a patriarchal bias where the guy doesn't suffer for being older and less likely to win a fight with a young stag. He gets the young/hot/childbearing female by dint of age and status. Which has its roots maybe in biology, because of course he needs a good young one to keep reproducing with.
For the older female, the young guy is equally sensible biologically, as his super-strong sperm are more likely to give her that last baby, I guess. And then when it's too late, at least she may as well have the comfort of a guy who respects her honed femininity, which encompasses not just the girl but also the female fully expressed as mother too. Hmm.
As you can see, I've thought a bit about this haha.
Feedback from my unofficial survey of 20+ guys:
Older women are kinder and more submissive.
Probably right.