I don't beleive it is more difficult for a woman, if she have a loving, caring partner. I have several girlfriends that say they have never had even one, but IMO, at least in their cases, it is because their husbands are more interested in their own satisfaction, not their wife's (which is a shame because it could be even better for the man if he made sure his woman was happy too).
The ages of the women they researched would effect it as well because it gets easier to have an orgasm as you get closer to your peak.
I also disagree with this. As a woman gets older, she can have as many circulation problems as a man, so it can either take longer or maybe not happen at all. The good news is there is help available.:)
I wouldn't be surprised if more than 80% of teen girls that are sexually active had never had one because their bodies aren't as developed as they need to be yet and they and their partners aren't as experienced.
I guess we disagree quite a bit, at least about teen girls bodies not being developed enough to have orgasms. I was a teenage girl a long time ago and I think that's about all I want to say about this.