In the episode Mother's Day, all robots had an antenna so she could reach them with a controller. But in "Bend Her", Bender's antenna was a sign of manhood and had to be removed for him to become a female robot. See more
[On TV, reenacting the wedding
Coilette, your death fills me with sorrow... anger, fear. Every emotion an actor can dislay.
Prof. Hubert J. Farnsworth
[to everyone watching TV
Turn off that crap-o-rama! One mistake now, and Bender will be trapped forever between the already ill-defined robot sexes.
[Uses a hammer and a chisel on Bender
Oh! Ooh! Ow! Ooh!
Philip J. Fry
Well, Bender, I hope this has taught you a lesson about changing your sex to win five gold medals.
It truly has. My romance with Calculon has shown me a lot ...