I read on Wikipedia today that the female orgasm has no reproductive use, whereas the male orgasm does. Who the hell comes up with this bollo**s? Firstly, orgasms by themselves cannot be directly related to reproduction, since the vast, vast, vast majority of living things reproduce just fine without them. Secondly, there is no such thing as purpose in evolution.
Our idea of purpose is something preconceived to serve a function. For example, a chair is made to be sat on. A typewriter is made to be typed with. A blog post is written to be read and shared. Evolution does not work that way. Nothing is ever made to serve any function because nothing is made according to a function, before that function exists. The concept of function itself is tightly dependent on the environment. A function is the relationship between two things which are connected to each other by cause, effect and time.
The only reason most things have a function in living things is because those that didn't, couldn't survive. The fundamental blueprint for life on Earth came to be the moment the very first, basic life form evolved. That is our common ancestor - of all alive today. Really, everything that came afterwards couldn't have been that far off the right recipe for life, since what it came from was a work of perfection (loosely, relatively speaking).
So what's the deal with this whole orgasm thing?
The idea suggested on Wikipedia is that orgasms encourage men to have sex, and since orgasms are associated with ejaculation of sperm, then that means that orgasm is involved in reproduction. On the other hand, female orgasms are not associated with an egg maturing, or anything like that, hence female orgasms are not involved in reproduction.
What results in reproduction in simple species, things such as mere chemical signals over a minuscule pathway, builds up to bigger things such as hormone secretion in dogs - and so the accumulation of these precursors is almost like an inheritance passed on to further species which diverge from the ancestors.
Would men have sex if they never knew of orgasms? Would women? Undoubtedly. Would men and women have more sex if they knew of orgasms? Certainly.
But such moment of truth never existed to start off with, because as humans, we have always been orgasming, and so have our ancestors further back. It's like having two ears was never up for selection, simply because it had been established a long time ago that that is the template. Women have orgasms, and while orgasms are not part of the zoomed-in mechanism of reproduction, they are part of the zoomed-out mechanism of reproduction.
Arguably, no one "knows" of orgasms before they have one, in the sense of actually knowing what it feels like. Yet they may still masturbate as children or teenagers, or even later on. The drive is not the orgasm initially, but the feeling of pleasure caused by stimulation - a feeling perhaps so basic that could be traced down many, many generations of species.