>>57764960While all Legendaries are assigned "Gender Unknown" in the code of the game, all the legendaries have assigned genders (with them even creating a second Mewtwo and making her female, as much to better display Mega Mewtwo Y as it was to avoid having to deal with Shudo's estate to get rights to his Mewtwo character) informed by their design influences (Ho-Oh, Kyogre, Palkia, Reshiram, Xerneas, Lunala, Zacian and Miraidon are all confrimed female in some fashion, while Groudon, Dialga, Zekrom, Yvetal, Solgaleo, Zamazenta and Koraidon are all confirmed male).
The fact Ho-Oh's based off the Fenghuang, a mythical creature once considered two distinct creatures (the Feng and the Huang, one male, one female) but long since taken to be a singular female creature (to allow pairing with the Masculine Dragon as a symbol for marital harmony) should have made you at least a little aware that game mechanics do not tell the full story (unless you're really that dumb, you thought the anime writers rolled an 8-sided dice to determine the gender of all the Delphox, Braixen, Fennekin, Popplio, Brionne, Primarina and Liko's Sprigatito/Floragata/Meowscarada and ended up breaking statistics by hitting the lowest value 8 times in a row).