Board Thread:General Discussion/@comment-27894627-20160511021754/@comment-28517551-20160731205407

Shadrixian wrote: It's a robot. Robots don't have a gender. Toby never specifies what gender Mettaton is. It is referred to as he, it, but never "she". Except one, by Alphys. I highly doubt she was referring to Clamgirl or Undyne. And yes, robots have genders, since they are built according to the physicality of one specific gender. (Otherwise it's a machine, cuz robots have humanoid bodies)