I am a boy and i am 20 years old . my father height 6"1.5".my mother is 5'3".but i am 5'8"at the age of 20.i want to grow 6 feet. boys grow till 25?

Very unlikely!: You can ask your Dad when he stopped growing but most boys stop growing by the age of 18. The most definitive test is called the "bone age" wherein they X-ray your wrist, hand, and fingers at once and compare it to an atlas of "standards". Your bones lengthen at the ends, not the middle. It will tell you how much potential growth you have left in your skeleton. Also read "Serenity Prayer".