Board Thread:Wiki Discussion/@comment-28440466-20160512075843/@comment-27701762-20160512093714

DarkAssasin999 wrote: Obviously not Mettaton or any other actally that undyne is the only main character in Waterfall and Mettaton does not go there until finishing Asriel Battle but Papyus WOULD NOT DO THAT EITHER so its must be alphys

Thus i earlier said if alphys and undyne would be the same sex which is lesbian and would have loved each other secluding that fact to its just crazy

Toby please tell us what gender is alphys Mettaton is perfectly capable of going to Waterfall "off-camera." He exists prior to the protagonist falling into the Underground. The implication of the line is that whoever Alphys's friend is visited Undyne along with Alphys. It would be incredibly out of place otherwise. Meanwhile the line cannot be referring to Alphys, since it is clearly referring to "Alphys's friend."

Again, Alphys is female. There is no question about this. Every single character and the game itself refers to Alphys as "she." Yes, the fact that both Alphys and Undyne are female and are coupled together makes them a lesbian couple.