This was always a topic i found interesting in a way ever since i first saw "when harry met sally". Throughout high school and my teens i had many female friends that i never slept with, never even tried, one of my best friends was a total knockout yet nothing. Then sometime around my early 20s things changed i started keeping a smaller group of friends, still had many female "friends" however given time spent together I'd consider them more so acquaintances, since then [10yrs] I've noticed the female friends that I've spent any significant amount of time with in many cases ended up in the bedroom, the ones that didn't were ultimately short lived friendships and we went our separate ways. The ones that did end up leading to the bedroom, some were mutually casual, some involved feelings either mutual or one sided. Its one of those questions that i think ends up being too simple of a question for an otherwise very dynamic situation with too many variables.