I think this would surely depend on a persons definition of casual? There are those experiencing one night stands with people they're not greatly familiar with - but it's worth mentioning that many of these situations are preceded by drink and sometimes drugs. Is it advisable to have such an intimate experience with someone whose medical/personal background you know nothing of? I would think a responsible adult with the benefit of years of life experience knows the answer to that one.

Then there are those who have regular sex with people they claim to be friends with. I personally would suspect the level of emotional involvement - oftentimes either party has more invested feelings in the other but daren't rock the boat and risk the situation altering into something less advantageous then the current one.

In short, there are advantages and disadvantages to being at different stages in life. And sometimes the desire for an experience we feel we've missed out on can be stronger then the reality. Excitement comes with a lot of risk - the benefit of being a fully fledged adult is that we realize the implications. So many are without such foresight. All the best.