Female orgasm probably does aid in the survival of the species, but what I find to be a much more interesting question from an evolutionary standpoint is, 'why don't females have musculature equivalent to males?' It would confer an obvious and significant advantage in both their survival and that of their children and it is also obviously something that the human body is capable of. I wouldn't even think that it would take very many generations for this trait to evolve. The fact that it hasn't is very interesting.
How stupid are these people. An obvious answer is that women will prefer a male and will have sex more often with a male who can induce orgasm. Anything that provides pleasure will be done more often.