I actualy dont see what is your problem here... HB gave you one solution and i gave you another...You dont need to set same variable name as he gave you, he made just example.
if you have male.txt and female.txt.... then you can use like HB told you spintax and make variable from its result. After that you use that new variable for determinating file path and name in list where you set file path you have files saved to, like: C:\......whatever is your path\{-yournew.variable-}.txt
then you just need to pull in line from list using list processing
Simple as that!
but as i said, there is always another solution, you can make folder where you have male.txt and female.txt in, and then you can get random file from folder and take line from it!