I agree with the former poster.. separate them. Put them together at select times to breed, but it's best if they live separately. The male will constantly harass the female and they will both get stressed out.
How long have they been co habbed? I agree that the tails look female (top) and male (bottom), but if they've lived together for years and you've never seen eggs you may have two males. Verifying gender via sight is nowhere near as reliable as trial breedings.