>>40267394>SylveonIt's an eeveelution, so that's easy. Although its Japanese name, Nymphia, implies that it should be considered female unless stated otherwise.
>PrimarinaThis is a bit trickier. As far as I remember, starter gender ratios were always 80/20 for a simple reason - more boys play Pokemon, and GF thought that boys wouldn't like it if their starters turned out to be girls half of the time. But making all starters 100% male was also a bad idea. So they went with the compromise, and gave all starters 80/20 gender ratios. That ratio stands to this day, and Primarina is just one of its victims.
Although I have no clue how anyone thought that giving a Pokemon, whose second evo is a literal fucking ballerina, a 50% male ratio was a good idea.
