While there's nothing particularly manly about the PSP, or feminine of the Nintendo DS, a recent survey by Net Asia Co of Japanese people shows a preference by each sex.
They conducted an internet poll of 401 mobile phone users ranging from the age of 15 to 29, asking what portable game console each person preferred. It's a bit strange that they decided to divide the Nintendo DS and the DS Lite in separate categories, but I suppose that some may prefer the "DS Phat."
For the guys, the majority (42%) picked the PlayStation Portable, beating out about 30% for the DS Lite and about 16% for the DS classic. In contrast, about 80% of the women polled chose the Nintendo DS in some form, with 52.2% picking the DS Lite. Only 8.8% of the ladies picked the PSP.
As for other interesting stats, TechOn says that the majority of these Japanese gamers don't get out much with their game systems. The majority (81.5%) say that they play their portable in their "room." What's the point of it being portable, then? That stat goes up (84.7%) when limited to only guys.
What about you? I suppose I fit with the Japanese figures, as I'm a guy and I prefer to play my PSP over my DS.