Here is the pic. I have tried combining and then merging vertices then converting but topology is all messed up. And when I tried difference it sometimes works but not always and works when I select the thigh first and then the hip, not the other way around. Since I can only attach one file the next reply will be my maya file attached. Seems the site is taking some time so I uploaded the maya files to mediafire.

Edit: Pic is too big and I fixed the boolean prob.