with these Japanese pickup lines
, they can only be used by men
the way they have been written here.
If a women would use them in such a way, she would either be considered lesbian (not a very cool thing when trying to hit on a cute guy) or simply crazy (~_~)/
Japanese is a pretty gender sensitive language. For example, the words "Boku" or "Ore" ("Me, I, Mine") can only be used by men. Women say Watashi or Watakushi, which is considered more politely (and can be used by men as well, if they want to be more polite).
Of course, women can have their say as well in the dating game, the pickup lines just need to have two versions: the male edition and the female edition.
One can find a large collection of Japanese love and fight language with gender connotations in a neat little book called "Making out in Japanese", written by Todd & Erika Geers. It tells a lot about dating in Japan, just by looking at what is usually being said in certain situations.