How come in anime the girls are never as strong as the guys!!!? GIRLS R STRONG 2?

well i know not in every anime girls r weak bit in some of them they suck. i mean the guys can fight but the girls cant? i mean especially in naruto the girls are ninja's yet they dont fight as good as the guys!!? i just recently watched the kakashi arc and rin is a medical ninja i know but she has ninja tools!!! tell me why she got heself captured when the guys kicked some serious *** i mean she could've done something!!! plz tell me your thoughts. (sry if any typos keybord is messd up)