I believe they did a study about something like this a long time back where they raised groups of kids together as part of it.

What they found was that the mind kinda put up a block around that to the point where most of the kids who were raised together just couldn't get that way about the kids they grew up with from a REALLY young age. I think they suspected it might be evolution's way of curtailing incest. Which is why you can have a very attractive group who just can't see each other in that way if they have been around each other since they were 4 or 5. I think they said that effect kinda reduced the older the kids got and those they met after around age 8 didn't have that affect at all for most of them.


Outside of that, if you are talking about just people who have known each other for years or decades. Pretty much it is all determined by the woman at that point as the guy will most likely try if he gets the green light regardless if they are attractive to them even mildly.

So basically, if the girl wants it, she has the option of turning it romantic even after decades. The guy mostly has zero say so and actually risks freaking her out if he even tries. And the girl will only want it if he looks good or is on the rebound and he is scavenging regardless of how nice the man is.