What do you think? While of course men are overall stronger and more athletic of course I think the biggest differences are two things: 1) the serve Relatively to the men women usually have harder groundstrokes compared to the serve. Girls like sharapove can hit consistently above 80 mph from the ground. this is not that much faster than the men (although they hit more spin and can go up to 100+ if they flatten out-while most girls always flatten it out). however on the serve very few women can hit 120 mph (there are a few of course) while a lot of men today can serve 135+. but the biggest difference is not the first serve speed but the second serve. even the harder serving girls who can serve 110+ usually have disasterous second serves. very few girls have a kicker. I think this difference is because of the biomechanics of the strokes. The forehand and even moreso the 2 handed BH are mainly driven by the hip and spine rotation. the arm is mostly "along for the ride". since girls have strong legs and hips compared to the upper body they can whack the ball hard since all the WTA girls now use the modern "rotational strokes". with the serve that is different. you also get a lot from the legs and trunk but to serve really hard you still need "an arm". serving is like overhead throwing (pitching). the legs help but you also need to be explosive in the shoulder and wrist. pitching coaches in baseball call this "a fast arm". very few women have that thus they often cannot serve. I think this is due to their body (relatively women have weaker upperbodies and stronger legs) but also due to the lack of overheadthrowing of girls as kids compared to boys. this of course changes the dynamic of the game. often serving becomes a disadvantage because the girls have very hard groudies but weak serves. 2) the second thing is the footwork there are very few fast women out there. that is the reason why very few women are successfull with a defensive game (woz is an exeption but she is having trouble too if the ballbashers have a good day). because of the weak movement the hard and flat slapping of the ball is rewarded. hitting the ball hard is the main goal of most girls. since they are not as strong as the men they need to hit with less spin or they would lose too much penetration from their shots (there are a few spinners but a lot of them are having trouble because they can't get enough on their shots and then get blown away). you basically have to bash the ball. if you are defensive your running will be too slow as a woman. and if you spin too much you lose depth and power and then you have to run again (you need a lot of RHS to hit really penetrating spin shots-weak spin shots dont do any good). so you have to slap hard. to capitalize on the weaker footwork the best thing in womens tennis is to just outhit the opponent. that is the reason why so many top players are ballbashers (williams, kvitova, maria, ivanovic...). with the men this is a little different. they all hit the ball hard too of course but the pure ballbashers like söderling are having trouble to succeed because the top men have so much footwork (and hit pretty hard too). just blasting one of the court like serena, kvitova or maria try to do doesn't work on todays slow courts with the men for that reason.