A while back a study at some elite university came up with research that found that women over the age of eighty were having less sex. This research actually tried to find out why that is so. All they really had to do was to visit any old age establishment and observe the ratio of elderly men to women.
Heaven for the man in his harem but not so for the ladies!
This is the sort of study that wastes precious resources but still the academics have to do something to get published, I guess.
Another of my favourite research results was that people who reached the age of eighty were more likely to reach ninety. I mulled over that one for a while and then was forced to agree that people who carked it before they reached eighty had very little chance of turning ninety.