I read somewhere that in women multiple orgasm is a learned response, and therefore women are more likely to experience it as they get older/more practiced at sex, making it correspondingly rare for first timers and young women. Whereas men tend to lose the ability to come more than once (always assuming they ever had it) as they age.
Don't you just feel SO sorry for those guys?
On the flip side - there has to be SOME compensation for periods/pregnancy/menopause!
'Purr