When buying a pair of rabbits, you will most likely be looking for a male and a female. The person selling the rabbits should be able to tell you what sex they are, but it is still a good idea to have a look for yourself.
Male or female?
Rabbits can be sexed rather easily. Ask the person selling you the rabbit to hold them whilst you look at its genital area. A male rabbit will have a round opening whereas a female rabbit has a slit.